Weaving Under Heavy Braking
Weaving Under Heavy Braking
Author
Discussion

Corpulent Tosser

Original Poster:

5,468 posts

268 months

Saturday 24th July 2010
quotequote all
Just had the car for a little over a week and getting used to it (Mk2 1800) Fitted new tyres a couple of days ago and they feel fine so far (Toyo T1-R).

On the way home tonight I decided to see how the brakes were and took the car to a around 70, checked there were no other cars around and braked very hard, the car immediately went into a weave, not drastic, stayed in my lane but very noticable.

Tyre pressures are OK, 26psi and the alignment was set 1-2deg toe in front and rear when the tyres were fitted.

Now my preference for a track car, which this will be soon, is slight toe out at the front but these settings were apparently the Mazda recomendation so I let it be set like that as a starting point, though if anything my prefered toe out should make it less stable.

So is this a common trait or is there a problem with my car ?

rfn

4,601 posts

230 months

Saturday 24th July 2010
quotequote all
Anything to do with the brakes perhaps?

I may not have understood what you've written correctly but is it possible that the brakes could be out of balance?

Corpulent Tosser

Original Poster:

5,468 posts

268 months

Saturday 24th July 2010
quotequote all
Possibly but it didn't pull to one side just a weaving motion.

I will try again tomorrow at different speeds to see if I can replicate the problem and maybe understand what is happening.

skinny

5,269 posts

258 months

Sunday 25th July 2010
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how new are the tyres? they take a little time to lose their surface agent from what i've heard...

on the other hand it may just be those tyres, i run t1r's now and find them a little 'busier' than tyres with conventional grooves (i.e. non v)

piefacemate

592 posts

194 months

Sunday 25th July 2010
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Does sound a lot like brake balance to me. Is it due an MOT? They test on the MOT and would be a cheap way of diagnosing.

The real Apache

39,731 posts

307 months

Sunday 25th July 2010
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Sounds more like worn ball joints or a shagged track rod end. Get it on a ramp and have a prod

skinny

5,269 posts

258 months

Sunday 25th July 2010
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how old is the car? worn suspension bushes would also give this effect

Corpulent Tosser

Original Poster:

5,468 posts

268 months

Sunday 25th July 2010
quotequote all
It was MOT'd in Jan so could be suspension, I am planning a change of all the bushings anyway so that might help.

Didn't get a chance to go out for a blast today as we are going on holiday tomorrow and Mrs Tosser has had me doing pre-holiday chores.

Thanks for the feedback

MX-5 Lazza

7,954 posts

242 months

Monday 26th July 2010
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Where was the alignment done and do you have the print-out of the settings?