Damian Harty (Prodrive) Questions Forum
10 October 2003, 07:58 PM
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I consider (fairly 
) intelligent
) intelligent
And yep, will be in Notts tomorrow night for the old boys big night out!
See yer then, Alex
PS. now put your track-day hand bag away!
10 October 2003, 10:41 PM
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Oops............. Didnt mean to start a war.
With regard to what has been said, yes things have ended their life rather quickly, like brake pads and discs, all my own fault. My first trackday at knockhill, coming up the hill to pits, several cars trying to get back into the paddock, I hold the brakes on the hill for maybe a minute or so. Result - front discs warped. Replaced with uprated discs. Did it myself, so replaced it myself. By the same token, if something totally unrelated stops working, ie map reading light, for instance, I would take it to the garage to be fixed on the warranty.
Do you think this is fair, or is the warranty nul and void, for everything????????
Paul
With regard to what has been said, yes things have ended their life rather quickly, like brake pads and discs, all my own fault. My first trackday at knockhill, coming up the hill to pits, several cars trying to get back into the paddock, I hold the brakes on the hill for maybe a minute or so. Result - front discs warped. Replaced with uprated discs. Did it myself, so replaced it myself. By the same token, if something totally unrelated stops working, ie map reading light, for instance, I would take it to the garage to be fixed on the warranty.
Do you think this is fair, or is the warranty nul and void, for everything????????
Paul
11 October 2003, 07:59 AM
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Mike (Wood) the "Drive", a Greek auto magazine, has a special edition about your company and although I read some "strange" comments regarding Imprezas tuning is quite complimentary and is the first time here that someone examine in depth what exactly you do and presents your succeses in Rally world!
"Meva Power" that is one of your distributors had very bad name in the past (they used to modify cars and sell them as new...strange bur true as I saw my self a case in central Subaru service of a "new" Legacy biturbo sold from them before it is imported in Europe!) but they also have a huge race experience and respect currently, I just mention it as many of us in Greece don't trust them and as myself we prefer to deal directly with you.
Officialy Subaru Hellas doesn't accept a three years warranty if a car is modified with your products, unofficialy all the Subaru mechanics accept the Prodrive parts as the only guarantied modifications and only in extreme conditions they refuse to service a Prodrive modified Impreza.
May be it isn't directly related with the previous conversation but just want to give a different view of warranties as I know first hand the local regulations in force (I support Subaru service and local Subaru dealer from my job).
JIM
"Meva Power" that is one of your distributors had very bad name in the past (they used to modify cars and sell them as new...strange bur true as I saw my self a case in central Subaru service of a "new" Legacy biturbo sold from them before it is imported in Europe!) but they also have a huge race experience and respect currently, I just mention it as many of us in Greece don't trust them and as myself we prefer to deal directly with you.
Officialy Subaru Hellas doesn't accept a three years warranty if a car is modified with your products, unofficialy all the Subaru mechanics accept the Prodrive parts as the only guarantied modifications and only in extreme conditions they refuse to service a Prodrive modified Impreza.
May be it isn't directly related with the previous conversation but just want to give a different view of warranties as I know first hand the local regulations in force (I support Subaru service and local Subaru dealer from my job).
JIM
11 October 2003, 11:13 AM
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After all that, I finally get some time to reply to the original question....
The matching of rim width to tyres varies greatly with tyres, as I'm sure you can imagine. Also, like many other things it depends what you want from the tyres.
To understand the mechanisms at play, you need to humour me and make a model tyre with your fingers: Hold up the left hand with the index finger pointing upwards and the thumb pointing straight to the right. It should make a clean "L" shape, I'll let you fold the other fingers down so it looks clearer. Now mirror that with the right hand and put the tips of the thumbs together. This is a model of the tyre in cross section, notionally well matched to the rim. If you flex the fingers, you get the flexing of the sidewalls to give you ride comfort and the thumbs are relatively unaffected - i.e. the contact patch.
Now, move the fingertips apart as if you're putting the tyre on a wider rim. The first thing you'll notice is that you can't flex your thumbs enough to keep the contact patch flat and so it lifts in the middle (where the thumbs meet). Real tyres do this too, so by putting the tyre on a wider rim you put more load on the shoulders and unload the centre of the contact patch. This is quite like what happens when a wheel doesn't have "enough" camber for the application; the shoulders overheat but the breakaway becomes more progressive. For this reason, some classic racing types deliberately use rims that are "too wide" for the new improved tyres to make them match the original car better (and make the breakaway easier for old buffers to keep up with) but on a modern car like an Impreza, set up for high performance tyres and driven by attentive chaps there's no real need.
To complete the experiment, move your fingertips closer together again to simulate a narrower rim. Nothing particularly bad happens immediately here, it's just that with the sidewalls bent in the ability of the tyre to absorb bumps without bottoming out on the rim is reduced. However, you'll note if you try and "flex" the tyre sideways like when it corners, it lifts the inside edge of the tyre and pushes the outside edge down onto the road. Every other element of the system is trying to do that already, so too narrow a rim means excess outer shoulder wear.
Note that going *slightly* wider than the "fingers upright" width means the opposite effect occurs and the inside edge is pressed onto the ground, evening out the contact patch pressure to some extent. This is in most senses the "optimum" rim width for which the tyre carcase is designed and is the combination we sell.
So, a slightly longer answer than Mike's but basically the same!
Damian
The matching of rim width to tyres varies greatly with tyres, as I'm sure you can imagine. Also, like many other things it depends what you want from the tyres.
To understand the mechanisms at play, you need to humour me and make a model tyre with your fingers: Hold up the left hand with the index finger pointing upwards and the thumb pointing straight to the right. It should make a clean "L" shape, I'll let you fold the other fingers down so it looks clearer. Now mirror that with the right hand and put the tips of the thumbs together. This is a model of the tyre in cross section, notionally well matched to the rim. If you flex the fingers, you get the flexing of the sidewalls to give you ride comfort and the thumbs are relatively unaffected - i.e. the contact patch.
Now, move the fingertips apart as if you're putting the tyre on a wider rim. The first thing you'll notice is that you can't flex your thumbs enough to keep the contact patch flat and so it lifts in the middle (where the thumbs meet). Real tyres do this too, so by putting the tyre on a wider rim you put more load on the shoulders and unload the centre of the contact patch. This is quite like what happens when a wheel doesn't have "enough" camber for the application; the shoulders overheat but the breakaway becomes more progressive. For this reason, some classic racing types deliberately use rims that are "too wide" for the new improved tyres to make them match the original car better (and make the breakaway easier for old buffers to keep up with) but on a modern car like an Impreza, set up for high performance tyres and driven by attentive chaps there's no real need.
To complete the experiment, move your fingertips closer together again to simulate a narrower rim. Nothing particularly bad happens immediately here, it's just that with the sidewalls bent in the ability of the tyre to absorb bumps without bottoming out on the rim is reduced. However, you'll note if you try and "flex" the tyre sideways like when it corners, it lifts the inside edge of the tyre and pushes the outside edge down onto the road. Every other element of the system is trying to do that already, so too narrow a rim means excess outer shoulder wear.
Note that going *slightly* wider than the "fingers upright" width means the opposite effect occurs and the inside edge is pressed onto the ground, evening out the contact patch pressure to some extent. This is in most senses the "optimum" rim width for which the tyre carcase is designed and is the combination we sell.
So, a slightly longer answer than Mike's but basically the same!
Damian
12 October 2003, 02:47 PM
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Thanks Damian
From what I understand going from the factory 17x7” with 215/45/17 to 18x8” with 225/40/18 only good think is at the end.
I’d like to ask you something else, in my new WRX03 I realized that the car seats 1cm lower from driver’s side (LHD), the car is completely standard, is this normal for the new age cars and why?
Since new it has a slightly creaking noise that comes from the front side only at very low speeds or stopped and only when I turn the steering wheel left-right, I believe it comes from the steering boots that are plastics on new models (in my classic turbo they are elastics) but after the above finding I wonder if the spring seats in wrong position (co-driver’s side/higher) and when I turn left right it creaks and is the reason the car doesn’t seat flat!
May be it’s personal problem but if the new cars aren’t flat it’s interesting to explain us why this happens.
JIM
From what I understand going from the factory 17x7” with 215/45/17 to 18x8” with 225/40/18 only good think is at the end.
I’d like to ask you something else, in my new WRX03 I realized that the car seats 1cm lower from driver’s side (LHD), the car is completely standard, is this normal for the new age cars and why?
Since new it has a slightly creaking noise that comes from the front side only at very low speeds or stopped and only when I turn the steering wheel left-right, I believe it comes from the steering boots that are plastics on new models (in my classic turbo they are elastics) but after the above finding I wonder if the spring seats in wrong position (co-driver’s side/higher) and when I turn left right it creaks and is the reason the car doesn’t seat flat!
May be it’s personal problem but if the new cars aren’t flat it’s interesting to explain us why this happens.
JIM
14 October 2003, 03:42 AM
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must thank u to damian-nice to have to have such an experianced voice about-may i ask him if he will allow any of his counterparts speak-im a bit of a newbie-got a MY01 on mods performance wise r de cat centre section and tail pipe-scared to go any further as i dont want engine packing up in xx amount of miles -so want to mod it carefully as not sure how long will kep this car-will damian please answer-i realise he is a busy chap but if he could email me privatley to help me out i would buy him so many pints or shorts as he wanted-anyway im rambling-take care room x
15 October 2003, 07:09 AM
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An engine question? Eeeyuw. Isn't that the thing with never enough torque, hot, oily smelly vibrating thing that messes up my mass balance? I saw one once but I don't know much about them...
But seriously, I'm not the man to ask about engines - I'm sure that others can answer better.
Damian
But seriously, I'm not the man to ask about engines - I'm sure that others can answer better.
Damian
15 October 2003, 06:56 PM
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Damian, here in Belgium, the choiche for another suspension is very limited. Therefore, I was planning to use an Intrax setup, custom made to suit my old shape GT. The original setup is very good but a little on the soft side for serious cornering and track work.
The only downside is that it's only height adjustable, (coilover system) but not for bump and rebound. ¨Personally I think that adjustable dampers are just a gizmo to cover up the crappy handling when you install them (and the clunking noise !!!)or when you really want adjustable dampers, they will be VERY expensive.
The Intrax set cost me only 650 £ with a 3 year warranty even when used on track....
But what is it about that adjustability (in damping) that everybody talks about, I don't think that you need that kind of technology on a road car.
The only downside is that it's only height adjustable, (coilover system) but not for bump and rebound. ¨Personally I think that adjustable dampers are just a gizmo to cover up the crappy handling when you install them (and the clunking noise !!!)or when you really want adjustable dampers, they will be VERY expensive.
The Intrax set cost me only 650 £ with a 3 year warranty even when used on track....
But what is it about that adjustability (in damping) that everybody talks about, I don't think that you need that kind of technology on a road car.
17 October 2003, 10:02 PM
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I second DJ140's question. We've had a long thread (or two) running about this and with no definitive answer, we are looking at other options. Speaking for myself. I'd love Prodrive kit (if only for quality and warranty reasons), but we need to know WHEN! :-)
Thanks.
Steve
18 October 2003, 12:47 PM
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For the 03 spring kit, I don't know the definitive answer. I do know the settings are established, mainly because I've driven the car fairly recently - I can't remember when but it was some time inside the last month. However, there are quite a few different things going on and I don't always keep my eye on the details of each individual one. I will see if I can tease an answer out of someone next week and post it in this thread.
I am trying to steer clear of 'specific' topics and stay more generally technical, though!
Damain
I am trying to steer clear of 'specific' topics and stay more generally technical, though!
Damain
18 October 2003, 07:58 PM
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We are still waiting for the production spec springs from our supplier. They are promised this month but I'm expecting that they'll miss their deadline again in a typically Germanic way. Let's hope they've produced what we asked for!
Mike
Mike
19 October 2003, 11:37 AM
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hi there ,just a couple of questions,i have a ppp uk my 99 4 door impreza with bumpsteer mod.,front anti lift kit,4 wheel alignment,goodyear gsd3 f1 tyres[16"];
1]how can i tighten the rear end up to combat oversteer so the car is as neutral as i can get it.[ie bigger wheels/drop links/rear anti roll bar?]
2]im going to put on a decat downpipe will a remap of the ecu give me more torque and power
thannks
1]how can i tighten the rear end up to combat oversteer so the car is as neutral as i can get it.[ie bigger wheels/drop links/rear anti roll bar?]
2]im going to put on a decat downpipe will a remap of the ecu give me more torque and power
thannks
19 October 2003, 08:49 PM
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(rubs eyes, reads again carefully) Someone who wants less oversteer? As a first step, try going down 5psi on the front tyres and up 5psi on the rear tyres. Directionally, this moves you away from oversteer. Try the car like this to see if it's the sort of thing you want. If it isn't, try the changes the other way round and see if that's more like what you want.
There are a lot of things that can be adjusted to make these changes more permanently and in a way that has less compromises than the tyre pressure route. However, which one is best depends a lot on when you are experiencing the problem oversteer. If you can be more specific about which circumstances exactly the car doesn't do what you want and what you have to do to fix it (in terms of driving style) then I'll be able to have a better go.
Presuming less oversteer is really what you want, a little toe in on the rear wheels can help. As can a little more camber on the rear wheels. More front anti-roll bar (i.e. bigger), more front damping, more front spring - all move in the direction you want. Putting bigger (i.e. wider) tyres on the back will increase the stability of the car a great deal and will certainly help you with any momentary oversteer that you get. However, it will push the car (no pun intended) more towards limit understeer and my experience of Imprezas generally is that they have plenty of understeer.
So, thinking this through I'm coming back to wondering if whether the rear of the car being a little loose isn't unnerving you and making you lift off, which in turn amplifies the problem by making the car rotate more. If at this point you're gripping the wheel you won't be getting good feedback from the steering wheel about where the back of the car is, which will make you even more nervous. All of this makes me want to better understand when you find the car oversteers in order to be able to give a better answer.
Damian
(Edit) P.S. I forgot to answer the downpipe question. Almost certainly a remap can give you more power and torque. Just be careful it doesn't hurt the engine!
[Edited by Damian Harty - 10/19/2003 8:52:42 PM]
There are a lot of things that can be adjusted to make these changes more permanently and in a way that has less compromises than the tyre pressure route. However, which one is best depends a lot on when you are experiencing the problem oversteer. If you can be more specific about which circumstances exactly the car doesn't do what you want and what you have to do to fix it (in terms of driving style) then I'll be able to have a better go.
Presuming less oversteer is really what you want, a little toe in on the rear wheels can help. As can a little more camber on the rear wheels. More front anti-roll bar (i.e. bigger), more front damping, more front spring - all move in the direction you want. Putting bigger (i.e. wider) tyres on the back will increase the stability of the car a great deal and will certainly help you with any momentary oversteer that you get. However, it will push the car (no pun intended) more towards limit understeer and my experience of Imprezas generally is that they have plenty of understeer.
So, thinking this through I'm coming back to wondering if whether the rear of the car being a little loose isn't unnerving you and making you lift off, which in turn amplifies the problem by making the car rotate more. If at this point you're gripping the wheel you won't be getting good feedback from the steering wheel about where the back of the car is, which will make you even more nervous. All of this makes me want to better understand when you find the car oversteers in order to be able to give a better answer.
Damian
(Edit) P.S. I forgot to answer the downpipe question. Almost certainly a remap can give you more power and torque. Just be careful it doesn't hurt the engine!
[Edited by Damian Harty - 10/19/2003 8:52:42 PM]
20 October 2003, 12:21 AM
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As you already mentioned Damian the best overall modification is the way we drive our cars!
The last few months I tried many things on roads and track days and my conclusion is that some lessons along with a good practice is the best you can do to go faster.
After all with my standard WRX03 by adding a harder rear anti roll bar (22mm), -1 degree camber front/zero toe, factory camber rear/1mm per wheel toe out (plus some very good practice) I am going much faster on the corners than my previous MY00 with more than 300ps and huge torque!
Yes my car suffers more from weight transfer, is smoother and softer overall but in the end I am going faster!
IMVHO for someone that don't drive his car very often on track days etc it's better to stay with factory suspension adding in worse case uprated springs (Prodrives my choice), some other gadgets (anti roll bars, links etc) and better brakes (even pads, disks) and you will be amazed how faster can you go! At least in Greece where tarmac isn't good and the suspension needs enough travel to work above potholes, imperfect roads and tight corners.
Why then we spend a fortune on engine tuning when suspension/brakes are more importants?
JIM
PS: Congratulations to Solberg / Subaru team for the Corsica Rally win!
[Edited by JIM THEO - 10/20/2003 12:27:01 AM]
The last few months I tried many things on roads and track days and my conclusion is that some lessons along with a good practice is the best you can do to go faster.
After all with my standard WRX03 by adding a harder rear anti roll bar (22mm), -1 degree camber front/zero toe, factory camber rear/1mm per wheel toe out (plus some very good practice) I am going much faster on the corners than my previous MY00 with more than 300ps and huge torque!
Yes my car suffers more from weight transfer, is smoother and softer overall but in the end I am going faster!
IMVHO for someone that don't drive his car very often on track days etc it's better to stay with factory suspension adding in worse case uprated springs (Prodrives my choice), some other gadgets (anti roll bars, links etc) and better brakes (even pads, disks) and you will be amazed how faster can you go! At least in Greece where tarmac isn't good and the suspension needs enough travel to work above potholes, imperfect roads and tight corners.
Why then we spend a fortune on engine tuning when suspension/brakes are more importants?
JIM
PS: Congratulations to Solberg / Subaru team for the Corsica Rally win!
[Edited by JIM THEO - 10/20/2003 12:27:01 AM]
20 October 2003, 10:37 PM
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damian basicaly because i have removed understeer from the front of the car with bumpsteer removal the back can step out if i boot it out of a junction to join a main road while im turning onto the main roador. i like to throw it into a corner when im driving along most times .just need some conter balance to match the massive front end grip and 0 understeer .i run 33psi fronts and 30psi rear .
21 October 2003, 08:44 AM
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That sounds great to me!
We have found with some heavily directional tyres that they have a 'loose' feeling where they allow some yaw at the rear before settling at a nice steady state. This is OK for some people but not so good for others as it can give a spooky feeling on turn in. If you are not used to oversteer then as Damian says you can make it much worse by lifting off the gas. Doesn't sound like you are having this problem though.
We generally run equal tyre pressures front and rear on the early cars which may well help how it feels.
Mike
We have found with some heavily directional tyres that they have a 'loose' feeling where they allow some yaw at the rear before settling at a nice steady state. This is OK for some people but not so good for others as it can give a spooky feeling on turn in. If you are not used to oversteer then as Damian says you can make it much worse by lifting off the gas. Doesn't sound like you are having this problem though.
We generally run equal tyre pressures front and rear on the early cars which may well help how it feels.
Mike
23 October 2003, 10:25 AM
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This needs clarifying - Mike Woods post of a few days ago re:
"Easy answer, if it wasn't right, we wouldn't sell that spec! The only time an 8x18 won't work is if you have either an early car (Classic shape) or a 5dr where you may get the tyres catching on the rear arch in extreme conditions"
It isn't strictly true. Use of the 18x8 on a wagon means that the rim can pick up the body not just the tyre. When you use a 18x7.5 rim then depending on the tyre choice the tyre can still pick up the body.
"Easy answer, if it wasn't right, we wouldn't sell that spec! The only time an 8x18 won't work is if you have either an early car (Classic shape) or a 5dr where you may get the tyres catching on the rear arch in extreme conditions"
It isn't strictly true. Use of the 18x8 on a wagon means that the rim can pick up the body not just the tyre. When you use a 18x7.5 rim then depending on the tyre choice the tyre can still pick up the body.
23 October 2003, 05:45 PM
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Damian
I don't know if this is too specific a question, but, if not, I'd really appreciate your input. If it is, maybe you could pass it over to Mike Wood!
From Wheels Tyres, and Brakes Forum:
http://www.scoobynet.co.uk/bbs/thread.asp?threadid=263303
I'm thinking about "upgrading" my rims and tyres from 16” to 17” on my “Classic” 98 Impreza and I’m looking for some help and advice!
I certainly like the look of 17" rims, but, from a performance standpoint, I'm concerned about a couple of things.
I'm aware (from searching on ScoobyNet) that the most common tyre sizes fitted on 17's are 205-45/17 and 215-40/17, and that, apart from the Pirelli P-Zero and the Dunlop SP 9000, there is practically nothing available in 205-45/17, while there are many more choices in 215/40-17.
However....
1. The load capacity (load index) of most high performance 215-40/17's that I've looked at (with the notable exception of Toyo's T1s) is some 125 lbs. LESS per tyre than Subaru recommends. This of course adds up to a car that is about 500 lbs. “under-tyred” in this respect. Does anyone have any thoughts and/or experience with problems arising from this "issue"?
2. And again, from a pure performance standpoint, for those who have gone from 16" rims to 17's, has it been worth it? Prodrive's Mike Wood is on record as saying that moving from 16" to 17" rims (on a Classic) is a more important performance upgrade than changing suspension. But Prodrive recommends a 205-45/17 (preferred) or a 215-45/17 P-Zero. I presume that the 215-45/17 tyre is recommended because of its' higher load rating.
I’m also thinking that, in order to maximize the contact patch of a 215 tyre on a 17 by 7 rim, a little under-inflation is in order to flatten it out, and this may negate some advantages of the lower sidewall.... maybe I'm better off staying with my 16 inchers!?
Ideas, opinions, and educated guesses are all very welcome!!
Thanks.
John
[Edited by superstring - 10/23/2003 6:37:07 PM]
[Edited by superstring - 10/24/2003 6:53:34 PM]
I don't know if this is too specific a question, but, if not, I'd really appreciate your input. If it is, maybe you could pass it over to Mike Wood!
From Wheels Tyres, and Brakes Forum:
http://www.scoobynet.co.uk/bbs/thread.asp?threadid=263303
I'm thinking about "upgrading" my rims and tyres from 16” to 17” on my “Classic” 98 Impreza and I’m looking for some help and advice!
I certainly like the look of 17" rims, but, from a performance standpoint, I'm concerned about a couple of things.
I'm aware (from searching on ScoobyNet) that the most common tyre sizes fitted on 17's are 205-45/17 and 215-40/17, and that, apart from the Pirelli P-Zero and the Dunlop SP 9000, there is practically nothing available in 205-45/17, while there are many more choices in 215/40-17.
However....
1. The load capacity (load index) of most high performance 215-40/17's that I've looked at (with the notable exception of Toyo's T1s) is some 125 lbs. LESS per tyre than Subaru recommends. This of course adds up to a car that is about 500 lbs. “under-tyred” in this respect. Does anyone have any thoughts and/or experience with problems arising from this "issue"?
2. And again, from a pure performance standpoint, for those who have gone from 16" rims to 17's, has it been worth it? Prodrive's Mike Wood is on record as saying that moving from 16" to 17" rims (on a Classic) is a more important performance upgrade than changing suspension. But Prodrive recommends a 205-45/17 (preferred) or a 215-45/17 P-Zero. I presume that the 215-45/17 tyre is recommended because of its' higher load rating.
I’m also thinking that, in order to maximize the contact patch of a 215 tyre on a 17 by 7 rim, a little under-inflation is in order to flatten it out, and this may negate some advantages of the lower sidewall.... maybe I'm better off staying with my 16 inchers!?
Ideas, opinions, and educated guesses are all very welcome!!
Thanks.
John
[Edited by superstring - 10/23/2003 6:37:07 PM]
[Edited by superstring - 10/24/2003 6:53:34 PM]
29 October 2003, 09:03 PM
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Hi Damian
I thought I'd try to condense my long rambling "question" from a few posts up into a more succinct query...once again, I hope this is not too specific
As I mentioned before, Mike Wood is on record as saying that moving from 16" to 17" rims (on a Classic) is a more important performance upgrade than changing suspension.
Since there are so few choices to be had in the 205/45-17 size, if I were to go with a 215/45-17 tyre (as oppoed to 215/40-17, because of load rating considerations) do you think I would realize any significant PERFORMANCE benefit over the same tyre in the standard 205/50-16 size (since there would be only a very slight decrease in sidewall height, a small increase in overall diameter and most certainly more unsprung weight)?
Also, and I could be wrong about this, I'm thinking that, in order to maximize the contact patch on a 17 X 7 rim, a 215 tyre might need to a little less air pressure, thereby softening the sidewall and perhaps negating, to some extent, whatever advantage the lower sidewall might have.
Thanks again!
John
[Edited by superstring - 10/29/2003 10:00:54 PM]
[Edited by superstring - 10/30/2003 5:40:55 PM]
[Edited by superstring - 11/17/2003 1:57:02 AM]
I thought I'd try to condense my long rambling "question" from a few posts up into a more succinct query...once again, I hope this is not too specific
As I mentioned before, Mike Wood is on record as saying that moving from 16" to 17" rims (on a Classic) is a more important performance upgrade than changing suspension.
Since there are so few choices to be had in the 205/45-17 size, if I were to go with a 215/45-17 tyre (as oppoed to 215/40-17, because of load rating considerations) do you think I would realize any significant PERFORMANCE benefit over the same tyre in the standard 205/50-16 size (since there would be only a very slight decrease in sidewall height, a small increase in overall diameter and most certainly more unsprung weight)?
Also, and I could be wrong about this
, I'm thinking that, in order to maximize the contact patch on a 17 X 7 rim, a 215 tyre might need to a little less air pressure, thereby softening the sidewall and perhaps negating, to some extent, whatever advantage the lower sidewall might have.Thanks again!
John
[Edited by superstring - 10/29/2003 10:00:54 PM]
[Edited by superstring - 10/30/2003 5:40:55 PM]
[Edited by superstring - 11/17/2003 1:57:02 AM]
10 November 2003, 01:36 AM
#210
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Join Date: Jan 2002
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Damian, I'm having the same problem as yhe chod in my classic. I have had bump steer done and it has removed all tendency to understeer, but means that the back end is far more eager to go when cornering or on roundabouts (especially in the wet).
After a couple of near misses at relatively slow speed in the wet, i would also like to reduce this tendency. Based on what has been discussed here, one of the things i am considering is changing my Toyo T1-S 205/50/16s for a set of 215/45/17s. Would this be effective and do you recommend a specific tyre?
What else can we do to reduce the tendency to oversteer in these circumstances?
thanks
After a couple of near misses at relatively slow speed in the wet, i would also like to reduce this tendency. Based on what has been discussed here, one of the things i am considering is changing my Toyo T1-S 205/50/16s for a set of 215/45/17s. Would this be effective and do you recommend a specific tyre?
What else can we do to reduce the tendency to oversteer in these circumstances?
thanks