Terrible handling on Rainsports

Terrible handling on Rainsports

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Discussion

scottliv

149 posts

49 months

Monday 24th June
quotequote all
I have recently put Yokohama Advan Fleva on the front of mine. They are performing well after a run to Le Mans and back. I did read that RS5s were a favoured tyre choice but did not want to put a tyre that is developed for rain use on a car that is predominantly used in the dry. There was not a great deal of choice in this size but this did seem one of the better tyres for the price.

rev-erend

21,473 posts

287 months

Monday 24th June
quotequote all
New tyres take a hundred miles to bed in to get rid of the mould release agent.

Stick with it a few weeks.

Having mismatched tyres front to rear also does not help.

Pebbles167

3,590 posts

155 months

Monday 24th June
quotequote all
rev-erend said:
New tyres take a hundred miles to bed in to get rid of the mould release agent.

Stick with it a few weeks.

Having mismatched tyres front to rear also does not help.
I think that's no longer the case, I use tyres fresh from delivery and that's when they perform best.

Regarding mismatched tyres though, that's a fair point.

8Speed

736 posts

69 months

Monday 24th June
quotequote all
rev-erend said:
New tyres take a hundred miles to bed in to get rid of the mould release agent.

Stick with it a few weeks.

Having mismatched tyres front to rear also does not help.
Agree 100%
I'd never have tyres mismatched front to rear.

motul1974

722 posts

142 months

Monday 24th June
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My experience of rainsports 3's is they needed a good 100 miles run in, after that they were like limpits in the grip department. Not very feel some at low speed, but great when throwing my chim about. Comparisons with heavy cars is pointless. I know they were primarily designed for them, but that's why I believe they work as a good all around tire on our cars - quite soft and grippy.

SMB

1,516 posts

269 months

Monday 24th June
quotequote all
I have toyos on my Griffith and rainsport 5 on the Chimaera, so have tried both. Both can benefit from a couple of extra psi, but You have lost probably 10% ish of the on road contact patch so By all means go back to Toyo, in the 245 size. but I would suggest an alignment is still needed.

If the alignment is set close to parallel or slightly toe out, you will get the symptoms you suggest, sharp turn in and nervous feeling on the road. Both front and back axles need to be right. Power steering on these cars can make it twitchy compared to a manual rack if the alignment isn’t right.

Std specs are for a little toe in, which gives some stability.

Edited by SMB on Monday 24th June 17:36

The Three D Mucketeer

6,026 posts

230 months

Monday 24th June
quotequote all
I always finish up with miss matched makes/specs of tyres on rear wheeled drive cars.... fronts last for ages and rears are bald smile .

Currently have Conti Sports on the front and TOYOs on the rear in summer, I find the mix OK .

I don't understand going to 225s on the rear , I have 235s on my Chim... and I don't understand why changing the rears make it tramline and bump steer ... I always thought that was front related and why i put my Tuscan on 225s BUT on the FRONT !!

Edit ... Although having 16" wheels all round increase my options
TOYO Snow Proxies for Winter


Edited by The Three D Mucketeer on Monday 24th June 19:09

Kawasicki

13,265 posts

238 months

Monday 24th June
quotequote all
lwt said:
Looked up Linear Range Oversteer and sounds a spot on description. As an ex aerospace test engineer I am familiar with aircraft ‘static’ and ‘dynamic’ flying qualities and this is similar. If it was an aeroplane it would be grounded until this major deficiency was corrected. Off to buy some Toyos this morning.
Good man.

Also try adding a little (0.1 bar) pressure to the rear axle and decrease the front by the same amount. This won’t fix a major issue though, like you have/had.

Other tricks are staggered tyre sizes (as found on most mid/rear engined cars), or steering racks positioned so that the steering input is effectively reduced once the outside front tyre starts generating lateral force (compliance understeer). The same issue is also improved through bump steer (toe) curves that also subtract steering angle from the outer front tyre and add steer angle (in the direction of the front axle) to the rear wheels.

Look up Bundorf analysis if you have a chance.


The Three D Mucketeer

6,026 posts

230 months

Monday 24th June
quotequote all
Kawasicki said:
Your car now has linear range oversteer (or was too little linear range understeer).

Good luck with that.

Easiest solution is swap the tyres front/rear.
What put 15" 205s on the rear ???? frown

lwt

Original Poster:

297 posts

287 months

Monday 24th June
quotequote all
Should get to try Toyos tomorrow. My slight concern is that the TR1 is of course different from the T1Rs that the car was set up for. Hopefully not that different.

For info, I have 16” all round as the front has a Wilwood big brake kit and sits on Nitrons all round. Just to clarify, with the Toyo T1R, 225 on the front and 245 at the rear at F22psi and R24psi, the handling was perfect, a pleasure to drive, and has been like that ever since a geo setup by Neil Garner at Kemble. The only thing that turned it into a hedge finder was fitting RS5s to the rear.

Update tomorrow and interesting to read all your comments!


Kawasicki

13,265 posts

238 months

Tuesday 25th June
quotequote all
The Three D Mucketeer said:
Kawasicki said:
Your car now has linear range oversteer (or was too little linear range understeer).

Good luck with that.

Easiest solution is swap the tyres front/rear.
What put 15" 205s on the rear ???? frown
Didn’t realise it had a staggered setup - sorry

The Three D Mucketeer

6,026 posts

230 months

Tuesday 25th June
quotequote all
Kawasicki said:
The Three D Mucketeer said:
Kawasicki said:
Your car now has linear range oversteer (or was too little linear range understeer).

Good luck with that.

Easiest solution is swap the tyres front/rear.
What put 15" 205s on the rear ???? frown
Didn’t realise it had a staggered setup - sorry
Original factory configuration was 15" front/16" rear , it would appear the OP has changed to 16" all round, as have a lot of people , me included. Mainly because of the lack of availability of W/Y/Z 15" tyres . But fronts are usually kept narrower compared to rears , I run 225/45 s and 235/50s on 16" to keep the rolling radius the same as original.

spitfire4v8

4,013 posts

184 months

Tuesday 25th June
quotequote all
I have the 5s on my tuscan racer track car .. what I would say is that they are absolutely fine once loaded up sideways, it's the transition from straight ahead to that first bit of side loading that is the issue .. it's even more apparent when you go from loaded one way to loaded the other ..

case in point being Craner Curves at Donington .. going down there you feel like the back of the car is on ice, you want to make a steering correction for oversteer even though that's not actually happened. Interestingly the effect is far more pronounced at the rear than the front, but it's a feeling of disconnection between the car and the road .. the car really does feel like it's flexing a llllloooonnngggg wwwaaayyyyy on it's sidewalls. Now obviously a sidewall can only flex so far, but the effect it creates feels out of proportion to the actual deflection of the tyre. It's very disconcerting.

Once loaded up sideways it seems absolutely fine, it's the transitional phase that is the issue for me.

sixor8

6,400 posts

271 months

Tuesday 25th June
quotequote all
The Three D Mucketeer said:
Original factory configuration was 15" front/16" rear , it would appear the OP has changed to 16" all round, as have a lot of people , me included. Mainly because of the lack of availability of W/Y/Z 15" tyres . But fronts are usually kept narrower compared to rears , I run 225/45 s and 235/50s on 16" to keep the rolling radius the same as original.
The original front tyre size was 205/60 x 15 which changed to 205/55 x 15 (225/50 x 15 with PAS on the 500). The rear tyre size at the factory changed from 225/55 x 16 to 225/50 x 16 after about 1994, probably due to the same speed rating issue. Then they went to 245/45 x 16 on the Griffith 500 and the Chimaera 500 towards the end of production, which is actually a bit marginal on a wheel that is 7.5" (190.5mm) wide!

The Three D Mucketeer

6,026 posts

230 months

Tuesday 25th June
quotequote all
sixor8 said:
The original front tyre size was 205/60 x 15 which changed to 205/55 x 15 (225/50 x 15 with PAS on the 500). The rear tyre size at the factory changed from 225/55 x 16 to 225/50 x 16 after about 1994, probably due to the same speed rating issue. Then they went to 245/45 x 16 on the Griffith 500 and the Chimaera 500 towards the end of production, which is actually a bit marginal on a wheel that is 7.5" (190.5mm) wide!
Only went to 16" because Wheeler couldn't get a deal on 15" tyres smile
Chim and Griff tyre changes were different , but both very varied 1993-1996 205/215/225 45/50/55/60 on the front and 225/235/245 45/50/55 on the rear ... I think dependent on what Brigestone S02 S03 were offering to Peter smile

Personally i think 50% profiles and above look like balloons on the front and drive like it )


Edited by The Three D Mucketeer on Tuesday 25th June 17:46

lwt

Original Poster:

297 posts

287 months

Tuesday 25th June
quotequote all
Well, Toyos are delayed and will be another week now, so getting the old worn ones put back on. Fortunately not yet collected for disposal!

Plan now is to keep these on while getting some independent advice on which way to go from TVR specialists. I would be quite happy to change all 4 and get a geo setup if thats what it takes to get my nice handling back.

Spitfire; yes, exactly that feel and I dont like it!

Kawasicki; thanks for pointing me at Bundorf, an interesting read and lots of aircraft parallels. If I may, could I point you at Longitudinal Static Stability for fixed wing aircraft.

Thanks all, and I will update when something happens. Good or bad.

carl350i

145 posts

253 months

Tuesday 25th June
quotequote all
Hi,

I fitted rainsport 5’s to my griffith last year, no complaints so far, I don’t use it on the track, more of a cruiser when I have the time. Hope you sort it out.