Searching for the perfect Chassis
21 September 2005, 04:14 PM
#151
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D2 first impressions
Drove back from Sittingbourne to Cambridge via the Essex twisties yesterday, after 'Impulse' fitted my D2 coilovers. Before it was standard WRX with tired dampers, now it's 6/4 kg/mm front/rear D2 coilovers, 20mm lower than standard with mid-range damper adjustment. Ride felt pretty compliant initially (a little more so than a pal's RA V-Lim for example) but quite jiggly over a 2-3hr trip. Good body control and turn-in once given a clear road, but frustrating having to follow commuter traffic through the narrow lanes!
It has just basic alignment at moment, but proper 4-wheel alignment will follow next week (inc front camber and caster) so am reviewing the various settings people have used.
On spring rates, there's a 5 kg/mm spring available for the front which I might try. That'd give a more conventional 5/4 front/rear ratio. 60/40 N/m has been mentioned for ASTs a few times here - what's the rationale behind this ratio?
cheers
Andy
It has just basic alignment at moment, but proper 4-wheel alignment will follow next week (inc front camber and caster) so am reviewing the various settings people have used.
On spring rates, there's a 5 kg/mm spring available for the front which I might try. That'd give a more conventional 5/4 front/rear ratio. 60/40 N/m has been mentioned for ASTs a few times here - what's the rationale behind this ratio?
cheers
Andy
21 September 2005, 05:58 PM
#152
IMHO:
I was told by several people ages ago to have the rear rate 80% of the front rate, so 50/40 is perfect.
I have tried this ratio on my AST's and the rates are very nice, especially on the road.
You need to dial the damping in carefully, but nice.
I am now at 60/50 so thats 100%/83% but the overal rate is a lot higher and the AST's are on the limit BUT fantastic on the track, and still nice on the road.
I like stiff chassis for the fun cars in my life, and I doubt that you could realy live with the 60/50 as a daily driver; the 50/40 may be a bit close to the edge also, but personal taste.
Trick is to get the damping right and that is simply trial and error.
Graham
I was told by several people ages ago to have the rear rate 80% of the front rate, so 50/40 is perfect.
I have tried this ratio on my AST's and the rates are very nice, especially on the road.
You need to dial the damping in carefully, but nice.
I am now at 60/50 so thats 100%/83% but the overal rate is a lot higher and the AST's are on the limit BUT fantastic on the track, and still nice on the road.
I like stiff chassis for the fun cars in my life, and I doubt that you could realy live with the 60/50 as a daily driver; the 50/40 may be a bit close to the edge also, but personal taste.
Trick is to get the damping right and that is simply trial and error.
Graham
23 September 2005, 12:48 PM
#153
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So I have been experiencing a clunking from the o/s front strut at low speed. Car is in currently for service and they looked at it and noticed that the front wheel can be lifted when the car is jacked up - looks like the damper has lost gas pressure. Anyway a quick call to the original fitter/supplier (Scoobyclinic), they have liaised with Powerstation and as a result I have arranged to go to PS next saturday to have the strut re-built and the car re-aligned.
I know that it is their responsibility to do this, but all parties have been very accommodating, no questions asked, just book it in to sort it. Good to be able to do it on a saturday at short notice, as I have 3 track days coming up and need to get it done quickly. A big thumbs up to everyone involved.
Weird thing is I drove the car at Cadwell (first time on the new suspension) with this problem and noticed no problems at high speed - wonder if the car is going to get even better when there is, er, gas in the damper!
I know that it is their responsibility to do this, but all parties have been very accommodating, no questions asked, just book it in to sort it. Good to be able to do it on a saturday at short notice, as I have 3 track days coming up and need to get it done quickly. A big thumbs up to everyone involved.
Weird thing is I drove the car at Cadwell (first time on the new suspension) with this problem and noticed no problems at high speed - wonder if the car is going to get even better when there is, er, gas in the damper!
23 September 2005, 05:24 PM
#154
When I was offered the ATS system from Powerstation Curtis took all the old AVO struts off. The two rears were well shot, little oil in them (no surprise) but I never noticed in the car even when hill climbing.
I put it down to my numb mind, but there you go!
Graham.
I put it down to my numb mind, but there you go!
Graham.
24 September 2005, 07:35 PM
#155
Saturday, and an action packed day at Prescott.
First practice run and the car jumped out of 1st gear leaving the line at 5000 rpm..
all is well, but I really thought it had finally gone. That slip cost me over 0.6 secs on the run. Rest of the climb was great.
Second run was much better, and netted a 48.09 (my best is 47.7), but the car still lifts a wheel or two, so I thought I would change the rear roll bar to 'softest' from middle position.
Third run........what a difference......in a really negative way! Tail slides everywhere, but strangely the time to the middle sector was the same, but lost out in the 'esses' bigtime to a 48.8. Will be going back to middle for tomorrow
You have to try these things.
Between runs we went to Powerstation to get some tyres for the EVO that darkens my class at these events. We went in his EVO RS competition car (he runs 46.4's) and this was quite interesting!
It has so much short gear punch (450 bhp) rather like an RA box and grips like mad.
At Powerstation we saw everyone (I think Fuzz was the only one working!) and tried to kid Ian Litchfield to load us his tuned Type C (I think he said yes..) for the hill climb, but saw the absolute killer V9 race car they have built....just so good it is untrue. I want one, the EVO man can buy one, but no offeres of a loan
Curtis showed me 'my' next generation struts to replace the road spec AST's I have currently, and they are just so nice.
Great day. Powerstation is very infectious, even the EVO man was taken by it all.
Ian reminded me that I can have a scoot in the tweeked Type C.......
Racing tomorrow.
Full class, 2 fast Nissan Pulsars, the EVO and I cannot mathmatically get 1st in class in the championship now, it has gone to the EVO. I will finish about 4 points behind him with a Nissan about 12 points in third.
Now, a 2.5/6 speeder/slicks/AST's just might do it....£6K?
Or that White race car in their workshop....
Report tomorrow night with some pics. Hope the box will last!
Graham
First practice run and the car jumped out of 1st gear leaving the line at 5000 rpm..
all is well, but I really thought it had finally gone. That slip cost me over 0.6 secs on the run. Rest of the climb was great.
Second run was much better, and netted a 48.09 (my best is 47.7), but the car still lifts a wheel or two, so I thought I would change the rear roll bar to 'softest' from middle position.
Third run........what a difference......in a really negative way! Tail slides everywhere, but strangely the time to the middle sector was the same, but lost out in the 'esses' bigtime to a 48.8. Will be going back to middle for tomorrow
You have to try these things.Between runs we went to Powerstation to get some tyres for the EVO that darkens my class at these events. We went in his EVO RS competition car (he runs 46.4's) and this was quite interesting!
It has so much short gear punch (450 bhp) rather like an RA box and grips like mad.
At Powerstation we saw everyone (I think Fuzz was the only one working!) and tried to kid Ian Litchfield to load us his tuned Type C (I think he said yes..) for the hill climb, but saw the absolute killer V9 race car they have built....just so good it is untrue. I want one, the EVO man can buy one, but no offeres of a loan
Curtis showed me 'my' next generation struts to replace the road spec AST's I have currently, and they are just so nice.
Great day. Powerstation is very infectious, even the EVO man was taken by it all.
Ian reminded me that I can have a scoot in the tweeked Type C.......
Racing tomorrow.
Full class, 2 fast Nissan Pulsars, the EVO and I cannot mathmatically get 1st in class in the championship now, it has gone to the EVO. I will finish about 4 points behind him with a Nissan about 12 points in third.
Now, a 2.5/6 speeder/slicks/AST's just might do it....£6K?
Or that White race car in their workshop....
Report tomorrow night with some pics. Hope the box will last!
Graham
25 September 2005, 09:11 PM
#156
Prescot today was very wet,slippy and bloody tricky.
Started by returning the rear roll bar to mid position and the car was fab.
Ended up second in Class, just 1.1 secs behind the Bloody EVO.
Finished second in class in the Championship also, so not too bad...maybe.
Wife took some video of the runs on the still camera, but Tiny pic doesn't do Video, who does a video host?
Graham.
Started by returning the rear roll bar to mid position and the car was fab.
Ended up second in Class, just 1.1 secs behind the Bloody EVO.
Finished second in class in the Championship also, so not too bad...maybe.
Wife took some video of the runs on the still camera, but Tiny pic doesn't do Video, who does a video host?
Graham.
Last edited by 911; 25 September 2005 at 10:23 PM.
26 September 2005, 06:45 PM
#157
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well done Graham, good to see the car is working well, i have a couple of mods to make to 3 way dampers then they should be ready for testing!
regards Curtis
regards Curtis
26 September 2005, 07:52 PM
#159
Videos:
This is driving me mad!
I have 2 nice action video's of the run but both are too big for Putfile. I can't compress the vids to 10Mb as they are 15.2 ish in size....
Any ideas anyone?
Curtis:
Sounding good!
Graham
This is driving me mad!
I have 2 nice action video's of the run but both are too big for Putfile. I can't compress the vids to 10Mb as they are 15.2 ish in size....
Any ideas anyone?
Curtis:
Sounding good!
Graham
26 September 2005, 09:06 PM
#160
Originally Posted by 911
Videos:
This is driving me mad!
I have 2 nice action video's of the run but both are too big for Putfile. I can't compress the vids to 10Mb as they are 15.2 ish in size....
Any ideas anyone?
Curtis:
Sounding good!
Graham
This is driving me mad!
I have 2 nice action video's of the run but both are too big for Putfile. I can't compress the vids to 10Mb as they are 15.2 ish in size....
Any ideas anyone?
Curtis:
Sounding good!
Graham
26 September 2005, 09:09 PM
#161
I am running Fuji finepics to try to compress the file but the system is just so un user friendly. I give up for tonight. Shame as the clips are quite good too!
Thanks for the advice...File 1: Successful!
Graham
Thanks for the advice...File 1: Successful!
Graham
Last edited by 911; 04 October 2005 at 09:42 PM.
02 October 2005, 08:06 PM
#162
The final hill climb has come and gone as of yesterday.
Bagged a first in class and a personal best too, so a good finish to the seaseon.
To the suspension:
This was the first time I had run the Sti with AST on the harder 60/50 spring rate that had been so good at Prescott.
Loton Park is a mile long through a tree-lined deer park tarmac track; a hill I know very well indeed with some very very challenging 'spots'. The Air ambulance is called on a frequent basis, so need to be careful.
Scare to one side, Fabulous!
The stiffer springs are spot-on for the track and apart from a little wheel lift here and there, impecable.
On the first practice run I ran with 10/12 front and 5/12 rear damping from soft, but went to 11/12 and 6/12 for the second which got the front quite a bit more stable, surprising difference.
Starts were a bit better too with less vertical bobbing about off the line when the weight shifts back on dumping the clutch.
The most mark inprovement with the 60/50 is the smooth transisition fron left-to-right-to-left type of rapid swerves so typical in hill climbs. The roll bars compliment the spring rates and I'm wondering if the Whiteline adjustable front might get me a bit further if fitted.(?)
In summary:
1
AVO 'things' off (good move)
AST's on 50/40 rates with 7/12 and 5/12 damping is Great for the road and the hills, very nice balance and smooth ride. Manhole covers etc are driven over as if the stock Sti suspension was on. Just about right for a daily driver if you like sports cars!
2
AST's with 60/50 springs and 10/12 and 6/12 damping are about the max you would want in a road/racer. Manhole covers are still ok, but watch it. The resulting jarr can be disconcerting. BUT, on the track the car is onto a very different higher level and simply inspire confidence, not to be stupid, but to feel the flow of the run through every move and makes it easy to fully concentrate on the best line for the bend ahead, and plan for the one after that too.
I wish I could take some of you onto a good hill to 'demonstrate' as my english is not too good at describing the changes.
3
So much good news you think; there is just one area for improvement i can think of for these Road Spec AST's and that is the 'click' of the damping adjuster wheel. 3 of 'mine' are nice and posative click, very easy to be sure how much you have dialed on, but the one is very ill defined so care needed to gat the dampers balanced accuratly.
Overall a great experience, and thanks to Powerstation for the oppertunity (and the demon alignments from Curtis) to try these great units.
I have shaved tons of time off my track times since fitting these, given the EVO Man a scare or three, and have NOT given myself a scare at any time.
Curtis is preparing the remove reservoir double action dampers now for the car with 60/50 springs. They look simply awsome on the bench and I sure hope to refine and repeat the success of this trial next year when the season opens in anger.
I want to try a private track day at Curborough to help dial-in the initial settings before the start.
Now, I've tried to master the video command on the camera, so I hope these small snippets from yesterday will amuse:
http://www.jusspress.com/daymainfram...004&imageNum=0
http://www.jusspress.com/day.php?use...entTime=171902
http://www.jusspress.com/day.php?use...entTime=134338
http://jusspress.com/day.php?userid=...entTime=161936
Graham
Bagged a first in class and a personal best too, so a good finish to the seaseon.
To the suspension:
This was the first time I had run the Sti with AST on the harder 60/50 spring rate that had been so good at Prescott.
Loton Park is a mile long through a tree-lined deer park tarmac track; a hill I know very well indeed with some very very challenging 'spots'. The Air ambulance is called on a frequent basis, so need to be careful.
Scare to one side, Fabulous!
The stiffer springs are spot-on for the track and apart from a little wheel lift here and there, impecable.
On the first practice run I ran with 10/12 front and 5/12 rear damping from soft, but went to 11/12 and 6/12 for the second which got the front quite a bit more stable, surprising difference.
Starts were a bit better too with less vertical bobbing about off the line when the weight shifts back on dumping the clutch.
The most mark inprovement with the 60/50 is the smooth transisition fron left-to-right-to-left type of rapid swerves so typical in hill climbs. The roll bars compliment the spring rates and I'm wondering if the Whiteline adjustable front might get me a bit further if fitted.(?)
In summary:
1
AVO 'things' off (good move)
AST's on 50/40 rates with 7/12 and 5/12 damping is Great for the road and the hills, very nice balance and smooth ride. Manhole covers etc are driven over as if the stock Sti suspension was on. Just about right for a daily driver if you like sports cars!
2
AST's with 60/50 springs and 10/12 and 6/12 damping are about the max you would want in a road/racer. Manhole covers are still ok, but watch it. The resulting jarr can be disconcerting. BUT, on the track the car is onto a very different higher level and simply inspire confidence, not to be stupid, but to feel the flow of the run through every move and makes it easy to fully concentrate on the best line for the bend ahead, and plan for the one after that too.
I wish I could take some of you onto a good hill to 'demonstrate' as my english is not too good at describing the changes.
3
So much good news you think; there is just one area for improvement i can think of for these Road Spec AST's and that is the 'click' of the damping adjuster wheel. 3 of 'mine' are nice and posative click, very easy to be sure how much you have dialed on, but the one is very ill defined so care needed to gat the dampers balanced accuratly.
Overall a great experience, and thanks to Powerstation for the oppertunity (and the demon alignments from Curtis) to try these great units.
I have shaved tons of time off my track times since fitting these, given the EVO Man a scare or three, and have NOT given myself a scare at any time.
Curtis is preparing the remove reservoir double action dampers now for the car with 60/50 springs. They look simply awsome on the bench and I sure hope to refine and repeat the success of this trial next year when the season opens in anger.
I want to try a private track day at Curborough to help dial-in the initial settings before the start.
Now, I've tried to master the video command on the camera, so I hope these small snippets from yesterday will amuse:
http://www.jusspress.com/daymainfram...004&imageNum=0
http://www.jusspress.com/day.php?use...entTime=171902
http://www.jusspress.com/day.php?use...entTime=134338
http://jusspress.com/day.php?userid=...entTime=161936
Graham
Last edited by 911; 05 October 2005 at 06:16 PM.
04 October 2005, 07:39 PM
#163
Graham, good to hear you are doing so well, you really are a 'dedicated developer' Have followed your " Antics " with great interest and decided to sprint my STi RA in the Midland Speed next season, I won't be a threat to you but it all sounds like too much fun to miss. Curborough is great especilally the lap and a half.
Andrew
Andrew
04 October 2005, 08:52 PM
#164
Glad to have spread a bit of happiness!
I can't stand Curb, but it is a great place to sprint and get going on the slippy slope of modding 'racing cars!
Watch out for the developing Subaru Sprint Championship next Year!!!!!!!!!
I hope to have a pop in that too.
I hope to see you next year now you are (or should be) committed
Graham
I can't stand Curb, but it is a great place to sprint and get going on the slippy slope of modding 'racing cars!
Watch out for the developing Subaru Sprint Championship next Year!!!!!!!!!
I hope to have a pop in that too.
I hope to see you next year now you are (or should be) committed
Graham
08 October 2005, 08:17 PM
#166
\m/ ^_^ \m/
apologies for not adding my thoughts to this thread Graham, never had time to read it properly 
well done on your results 
well done on your results
08 October 2005, 09:24 PM
#167
Thanks Flat!
Project's have been a bit thin recently.
Hope you have lots to do and keep us entertained over the next 6 months!
Tried to interest the wife in going to the Pod tomorrow, but no chance. Pity, as she is a bit of a petrol head too.
Pop those plugs in and get there!
Graham.
Project's have been a bit thin recently.
Hope you have lots to do and keep us entertained over the next 6 months!
Tried to interest the wife in going to the Pod tomorrow, but no chance. Pity, as she is a bit of a petrol head too.
Pop those plugs in and get there!
Graham.
08 November 2005, 01:01 PM
#168
The car has been up on the stands and i've stripped and re-greased the suspension to hopefully stop the groaning from the front ever since i put the ALK in.
Everything looked ok with no suspension damage despite some enthusiastic off's over the season, and some full blooded attacks over the curbs...
The Kumho tyres are totally sh@gged on the 16's and it is time to look for some fresh rubber.
Slicks are out unless I can find the $$$ for a 6 speeder (wife's not too 'helpful') so it will be list 1B tyres.
Anyone have any thoughts on just how big/wide I can go on the 16 x 7 Sti rims?
I currently have 205 45 16, but would like to squeeze under the classic arches something wider, 215 x 45 16 could be ok, but can I get more on?
I hope still to have the demon AST's for next year if my 'sponsor' (Powerstation) is willing.
Anyone?
Graham.
Everything looked ok with no suspension damage despite some enthusiastic off's over the season, and some full blooded attacks over the curbs...
The Kumho tyres are totally sh@gged on the 16's and it is time to look for some fresh rubber.
Slicks are out unless I can find the $$$ for a 6 speeder (wife's not too 'helpful') so it will be list 1B tyres.
Anyone have any thoughts on just how big/wide I can go on the 16 x 7 Sti rims?
I currently have 205 45 16, but would like to squeeze under the classic arches something wider, 215 x 45 16 could be ok, but can I get more on?
I hope still to have the demon AST's for next year if my 'sponsor' (Powerstation) is willing.
Anyone?
Graham.
08 November 2005, 01:18 PM
#169
I've had all sorts of groans and clonks since the Whiteline stuff was fitted, can't see anything amiss though and carry on regardless 
I have 225/45/17 from new age STi et 38 iirc on mine with either Bridgestone RE070s or Yoko A048s. I need 3mm spacer on the rears to prevent the 040s touching the strut but not with the Yokos. I did have 18" Speedlines with Pirelli P Zero (same tyre section) et45 but needed the rear wheel arches rolling.
The tyre section seems critical, 040s & P Zeros are a very square section where the Yokos are more triangular. I think 215s are about the limit on a classic without messing about too much.
I have 225/45/17 from new age STi et 38 iirc on mine with either Bridgestone RE070s or Yoko A048s. I need 3mm spacer on the rears to prevent the 040s touching the strut but not with the Yokos. I did have 18" Speedlines with Pirelli P Zero (same tyre section) et45 but needed the rear wheel arches rolling.
The tyre section seems critical, 040s & P Zeros are a very square section where the Yokos are more triangular. I think 215s are about the limit on a classic without messing about too much.
08 November 2005, 08:35 PM
#170
Thanks for that Gerry, I thought 215 would be the max.
The Kumho's are bolt upright 90 degrees to the rim so might be able to stretch a bit more.
Regards, Graham.
The Kumho's are bolt upright 90 degrees to the rim so might be able to stretch a bit more.
Regards, Graham.
08 November 2005, 10:37 PM
#171
Can you try 40 profile .. bit more clearance and you may get away with 225's ... and anyway if not 225's then on 215/40 lower rolling radius = lower gearing so faster acceleration!
I have 215/45x17s on my classic wagon, ( off a 2003 WRX ) std tyres, but these are too big a rolling radius really so I need 215/40's to restore speedo accuracy etc, ( and a smidge better acceleration! ) to match the old 15"'s that were OEM on my car.
I have 215/45x17s on my classic wagon, ( off a 2003 WRX ) std tyres, but these are too big a rolling radius really so I need 215/40's to restore speedo accuracy etc, ( and a smidge better acceleration! ) to match the old 15"'s that were OEM on my car.
14 November 2005, 08:12 PM
#172
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Hi Graham, Gerry and all,
I'm wondering what tyres to run next, after comprehensively rutting/nibbling my T1S's at Bruntingthorpe on Saturday. What Kumhos do you run Graham? A pal's 205 Mi16 on the same day was running Kumhos and they had just very fine rolls of rubber over the surface - lovely, just like you get on a racing bike tyre when the suspension's working well.
I also wondered if I can usefully run lower profiles. Wheels are Rays Volks 16" with 205/50 T1S currently, kept specifically for trackdays and hopefully sprinting/hillclimbing next year. Seems to be reasonable selection in 215/40-16, less so in 205/40-16, but I wonder if these would work well. Am interested purely in handling, grip, acceleration and eligibility for competition use next year.
In the meantime, have been offered some secondhand medium/hard Avon slicks - I wonder if they'd be worth a punt for the next trackday? (SIDC at Brands, 6th Feb, £99, book soon if you're interested!)
cheers
Andy
I'm wondering what tyres to run next, after comprehensively rutting/nibbling my T1S's at Bruntingthorpe on Saturday. What Kumhos do you run Graham? A pal's 205 Mi16 on the same day was running Kumhos and they had just very fine rolls of rubber over the surface - lovely, just like you get on a racing bike tyre when the suspension's working well.
I also wondered if I can usefully run lower profiles. Wheels are Rays Volks 16" with 205/50 T1S currently, kept specifically for trackdays and hopefully sprinting/hillclimbing next year. Seems to be reasonable selection in 215/40-16, less so in 205/40-16, but I wonder if these would work well. Am interested purely in handling, grip, acceleration and eligibility for competition use next year.
In the meantime, have been offered some secondhand medium/hard Avon slicks - I wonder if they'd be worth a punt for the next trackday? (SIDC at Brands, 6th Feb, £99, book soon if you're interested!)
cheers
Andy
14 November 2005, 09:15 PM
#173
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Thanks To You
Graham,
Your time and dedication to this thread is outstanding, i hope i can be of assitance to you in your quest of chasing that EVO next season, i hit the big 50 in jan, so perhaps we could approach SAGA about sponsoring a two car team, It`s going to be a long busy winter in the workshop, but what the hell you only grow old once.
John
Your time and dedication to this thread is outstanding, i hope i can be of assitance to you in your quest of chasing that EVO next season, i hit the big 50 in jan, so perhaps we could approach SAGA about sponsoring a two car team,
It`s going to be a long busy winter in the workshop, but what the hell you only grow old once.John
14 November 2005, 10:54 PM
#174
Another 50+ guy! Bloody hell, i though everyone was 30 somethings on here..
I have used Kumho V700 soft compound 205 x 16 x 45 which are stunning.
Road legal too, BUT, beware of your Championship's regs!
They even lasted 2 seasons (5000 road miles, 22 hill climb weekends)
I need all the tuition i can get. The EVO is killer.
Roy is 60!
Graham.
I have used Kumho V700 soft compound 205 x 16 x 45 which are stunning.
Road legal too, BUT, beware of your Championship's regs!
They even lasted 2 seasons (5000 road miles, 22 hill climb weekends)
I need all the tuition i can get. The EVO is killer.
Roy is 60!
Graham.
15 November 2005, 12:12 AM
#175
Originally Posted by vulnax999
Can you try 40 profile .. bit more clearance and you may get away with 225's ... and anyway if not 225's then on 215/40 lower rolling radius = lower gearing so faster acceleration!
I have 215/45x17s on my classic wagon, ( off a 2003 WRX ) std tyres, but these are too big a rolling radius really so I need 215/40's to restore speedo accuracy etc, ( and a smidge better acceleration! ) to match the old 15"'s that were OEM on my car.
I have 215/45x17s on my classic wagon, ( off a 2003 WRX ) std tyres, but these are too big a rolling radius really so I need 215/40's to restore speedo accuracy etc, ( and a smidge better acceleration! ) to match the old 15"'s that were OEM on my car.
205/50/16 = diameter of 611.4mm
215/40/17 = 603.8
215/45/17 = 625.3
225/45/17 = 634.3
205/45/16 = 590.9
Comparing the speedo accuracy with GPS, 225/45 are almost spot on agreement. Presumably poorer acceleration as you say (not noticeable with 2.5
)but less wheelspin and less ABS activity due to greater footprint even with bigger brakes.Gerry
15 November 2005, 12:45 PM
#176
My Kumho's are 590mm dia when new.
this gives snappier steering (lowered the car) Better brakes from my stock V3 stoppers, and better accelleration as the rolling dia is (a little) less.
Graham.
this gives snappier steering (lowered the car) Better brakes from my stock V3 stoppers, and better accelleration as the rolling dia is (a little) less.
Graham.
02 December 2005, 11:46 AM
#177
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911, very interesting thread sorry I have only just picked it up.
I currently run in the scottish sprint championship and do a couple of hills. Plan to do the full hillclimb this year. Currently working on the suspension set up and your comments are valuable.
I also ran with the Kumho 250/45x16 in soft but totally destroyed these. Went through 2 sets and missed the last race.
run a number of tyres pressures but not a much as 30 as i think you state. More like 22 to 25. Couldnt stop them melting! and specifically in the middle band which is usually an indication of too much pressure.
Have opted for the dunlop DO1J in the 205/50x16 in soft to see how these compare.
I relation to your quest for wider rubber i currently use Group A alloys which has the wider offset. Car is much more stable and you probably could get a wider tyre on the rim. I have 6 wheels spare if your were interested.
Cheers
za
I currently run in the scottish sprint championship and do a couple of hills. Plan to do the full hillclimb this year. Currently working on the suspension set up and your comments are valuable.
I also ran with the Kumho 250/45x16 in soft but totally destroyed these. Went through 2 sets and missed the last race.
run a number of tyres pressures but not a much as 30 as i think you state. More like 22 to 25. Couldnt stop them melting! and specifically in the middle band which is usually an indication of too much pressure.
Have opted for the dunlop DO1J in the 205/50x16 in soft to see how these compare.
I relation to your quest for wider rubber i currently use Group A alloys which has the wider offset. Car is much more stable and you probably could get a wider tyre on the rim. I have 6 wheels spare if your were interested.
Cheers
za
02 December 2005, 03:25 PM
#178
Za:
Glad this thread is of interest, especially to a fellow hill climber.
Those Kumho's are not 1B listed I think?
Interesting about the tyre pressures. I used to run my Kumho V70 soft @ 30 all round, but one meeting (twisty Prescott) dopped them each practice run and ended up at 25 all round.
Now, considering the Sti is nose heavy I should raise the fronts or reduce the rears to get a bias, say 25/22 Fr/Rr.
The temperature spread over the tyre width has been very even (measured by hand as soon as I had stopped after a run) and they looked like this:
Wouldn't the Group A wheels' offset be detrimental on otherwise stock suspension components?
The EVO which I have never beaten runs the 1B Dunlops, and i am very tempted to try them, but have a lot of confidence in the Kumho V70 soft.
Mine have lasted 2 seasons and 4000 road miles, so I think i need to try harder....
Graham.
Glad this thread is of interest, especially to a fellow hill climber.
Those Kumho's are not 1B listed I think?
Interesting about the tyre pressures. I used to run my Kumho V70 soft @ 30 all round, but one meeting (twisty Prescott) dopped them each practice run and ended up at 25 all round.
Now, considering the Sti is nose heavy I should raise the fronts or reduce the rears to get a bias, say 25/22 Fr/Rr.
The temperature spread over the tyre width has been very even (measured by hand as soon as I had stopped after a run) and they looked like this:
Wouldn't the Group A wheels' offset be detrimental on otherwise stock suspension components?
The EVO which I have never beaten runs the 1B Dunlops, and i am very tempted to try them, but have a lot of confidence in the Kumho V70 soft.
Mine have lasted 2 seasons and 4000 road miles, so I think i need to try harder....
Graham.
Last edited by 911; 02 December 2005 at 03:30 PM.
02 December 2005, 07:19 PM
#179
Tyres the big question, I'm also wasting all my Kids inheritance on sprinting and hillclimbing and have bought a set of Yoko 205/50/16, 32R's for next season for £96 plus VAT each, hope it is a good price. I have also been scratching my head as wife is complaining about a set of 17' Prodrive Alloys under the bed. Considered a set of 215/40/17 Avon ZZr's but at nearly £700 " Computer says NO " . I used to run my ZZ3 16" at 36 front and 33 rear so very interested in 911's low tyre pressures. West Country regs won't allow sections under 50, pays to do a bit of research first. Kumho V70A's are quite popular, though didn't have a 215/40/17 section.
02 December 2005, 09:37 PM
#180
Remember that the Kumho V70's in 17's are only available in Hard/medium.
I have a set of 205 40 17 on P1 wheels and hill climbed on them for a season.
The soft in 205 45 16 are miles better.
Graham
Inheretance? All gone. I've been hill climbing for 13 years, all gone!
I have a set of 205 40 17 on P1 wheels and hill climbed on them for a season.
The soft in 205 45 16 are miles better.
Graham
Inheretance? All gone. I've been hill climbing for 13 years, all gone!