FAO - Baz Hartech......
FAO - Baz Hartech......
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Discussion

Vesuvius 996

Original Poster:

35,829 posts

301 months

Wednesday 24th January 2007
quotequote all

Baz

Quick bit of advice, if I may be so bold.....


I just had to buy a new rear tyre due to a craft knife puncture which couldn't be repaired.

The other rear is about 1/3rd worn.


Obviously the rolling circumference of the slightly worn tyre is slightly smaller than the new one (by a factor of 2 x pi x Radiusdifference.) This will be a very small difference, but does this have any potential for causing problems with drivetrain/diff etc.. or am I paranoid....?

i.e do I need (if I am being ultra careful) to buy another rear tyre for the other side......


Thanks.





Edited by Vesuvius 996 on Wednesday 24th January 09:59

paracetamol

4,267 posts

274 months

Wednesday 24th January 2007
quotequote all
does your warranty not cover this

slippydiff

16,424 posts

253 months

Wednesday 24th January 2007
quotequote all
Vesuvius 996 said:

Baz

Quick bit of advice, if I may be so bold.....


I just had to buy a new rear tyre due to a craft knife puncture which couldn't be repaired.

The other rear is about 1/3rd worn.


Obviously the rolling circumference of the slightly worn tyre is slightly smaller than the new one (by a factor of 2 x pi x Radiusdifference.) This will be a very small difference, but does this have any potential for causing problems with drivetrain/diff etc.. or am I paranoid....?

i.e do I need (if I am being ultra careful) to buy another rear tyre for the other side......


Thanks.





Edited by Vesuvius 996 on Wednesday 24th January 09:59


Totally completely and utterly paranoid Soovie.
Nowt to worry about whatsoever. No new tyre required. Have a beer instead




Edited by slippydiff on Wednesday 24th January 11:08

Vesuvius 996

Original Poster:

35,829 posts

301 months

Wednesday 24th January 2007
quotequote all
paracetamol said:
does your warranty not cover this


Oh my aching sides.



Edited by Vesuvius 996 on Wednesday 24th January 11:56

rude-boy

22,227 posts

263 months

Wednesday 24th January 2007
quotequote all
Not a scientific answer to the question but I would say it was a question of degree. For example if your tyres last, say 10,000 miles and the 'worn' one had done 5K+ I would have thought it sensible if you were going to be pushing on in the near future. If we are only talking about, say 2k difference then I wouldn't bother. Had a similar thing when an Ex took a knife to one of my tyres a number of years ago. As both tyres would have been due to be replaced in a couple of months I had them both done. Yet when i burst a side wall on a broken kerb stone in a car park that I hadn't seen I only replaced the damaged tyre as the other side was only a few K miles old. At the time I was doing a lot of very enthusiastic driving and didn't notice any difference once I’d done the usual 'gentle' 200miles or so to bed in the new tyre.

Vesuvius 996

Original Poster:

35,829 posts

301 months

Wednesday 24th January 2007
quotequote all
rude-boy said:
Not a scientific answer to the question but I would say it was a question of degree. For example if your tyres last, say 10,000 miles and the 'worn' one had done 5K+ I would have thought it sensible if you were going to be pushing on in the near future. If we are only talking about, say 2k difference then I wouldn't bother. Had a similar thing when an Ex took a knife to one of my tyres a number of years ago. As both tyres would have been due to be replaced in a couple of months I had them both done. Yet when i burst a side wall on a broken kerb stone in a car park that I hadn't seen I only replaced the damaged tyre as the other side was only a few K miles old. At the time I was doing a lot of very enthusiastic driving and didn't notice any difference once I’d done the usual 'gentle' 200miles or so to bed in the new tyre.


yikes

Thanks. I was more concerned about whether the drivetrain might be in some way "out of balance" with one tyre marginally larger than the other....



whoami

13,201 posts

270 months

Wednesday 24th January 2007
quotequote all
Vesuvius 996 said:
paracetamol said:
does your warranty not cover this


Oh my aching sides.



Edited by Vesuvius 996 on Wednesday 24th January 11:56


Does it cover those as well??

diesel130

1,549 posts

242 months

Wednesday 24th January 2007
quotequote all
Should be OK if they're not wildly different. But if you're going on a track-day, then put the larger wheel on the left-hand side for brands, silverstone, spa etc, or on the right if you're at imola or interlagos !! :-)

Pork_n_Beem

1,164 posts

255 months

Wednesday 24th January 2007
quotequote all
If your car is 2WD and an open diff, i.e. not slippy diff, then there is no stress on the drivetrain, its just like going around a long corner and the ABS should not be affected. You might find some small rear steer effect.

If the car has an LSD, then in a straight line you will be in effect going around a corner and making the diff tighten up more so under power causing a small amount of wear in the diff.

If the car is 4WD, then you will have altered the average speed of the rear wheels and putting a new tyre on the rear will reduce the % torque applied to the front. Now problem for the drivetrain and ABS and TC should not be affectde

Whether you can tell any difference, don't know never done it

purds

115 posts

238 months

Wednesday 24th January 2007
quotequote all
Vesuvius 996 said:

I was more concerned about whether the drivetrain might be in some way "out of balance" with one tyre marginally larger than the other....





The differential will compensate for this in exactly the same way it does when the car corners and the outside wheel travels further than the inside wheel.

Dr S

5,153 posts

256 months

Wednesday 24th January 2007
quotequote all
Would this mean that after a few sharp and speedy lefthanders and then a few long and slow righthanders I should be worried about the balance and the drivetrain of my car?

utsonhisbetterbesafesmart*ssface:

Pork_n_Beem

1,164 posts

255 months

Wednesday 24th January 2007
quotequote all
Also under high power with a LSD, the diff will try and spin up the new tyre increasing wear, all marginal of course

chrispa

1 posts

250 months

Wednesday 24th January 2007
quotequote all
If you have PSM, then I've been told that this can be upset by different tyre diameters, I cann't remember what the critical difference is, however someone else may know

Vesuvius 996

Original Poster:

35,829 posts

301 months

Wednesday 24th January 2007
quotequote all


Poverty spec, mate. I'm OK on that score!!

nervous

24,050 posts

260 months

Wednesday 24th January 2007
quotequote all
i had a blow out in my '3 and at the time could only get 1 tyre, stuck as i was in the shit hole of the universe.

my tyres had about 1500 miles on them when it blew.

it definitley had a marked effect on the handling of the car and it felt decidedly nervy under acceleration after that, and never evened out in the 1500 miles i tried to stick it for.

sorry soov, if it were me id replace em both. not worth risking your neck over 150 sheets.

Bull996

1,442 posts

239 months

Wednesday 24th January 2007
quotequote all
When I changed 1 tyre on the back of my BM 5 series it sent the traction control in to fits and the auto box giddy too. Didnt like it at all!

graeme73s

7,228 posts

247 months

Wednesday 24th January 2007
quotequote all
sorry mate but I agree with Nerv' new rear tyre please.

Vesuvius 996

Original Poster:

35,829 posts

301 months

Wednesday 24th January 2007
quotequote all

Right, new tyre it is. Nervy, you're right. No point risking it for the price of a curry hehe

nervous

24,050 posts

260 months

Wednesday 24th January 2007
quotequote all
reckon youre worth more to us than 150 quid mate, be safe thumbup

giw12

1,462 posts

293 months

Wednesday 24th January 2007
quotequote all
nervous said:
reckon youre worth more to us than 150 quid mate, be safe thumbup


Close call though.....