Bottoming out on 18's
Discussion
Need some advice here.
Scene Setting - Required Intro
Problem below is neither due to cramming 4 in the Cerb or trying for Vmax through every countryside lane ... By self classification, I'm hardly a great driver living for every corner - just pootling around enjoying the burbles is enough for me.
Intro Complete
Cerb's running on 18" rims. Basically, I find that whenever out on some seriously undulating roads (generally B's, although it still does happen on the M6), I'll bottom out against the rear tyres a couple of times throughout the journey. Infact, it's now got to the point that I brace in expectation for most troughs in the road to be accompanied with the now familiar aroma of burning rubber ...
Tyre rim wear is even i.e. suggesting that both rear springs are being compressed equally and this is caused simply by the wheels being too big within the arches.
My thoughts are now as follows - will upgraded suspension help this in anyway ? Or, are 18's just simply a bit too big and it doesn't matter what lb'age springs are fitted on the rear, this is still going to occur ... ?
If we reckon that an upgrade is worthwhile (not just based purely for handling reasons - see intro - doubt I would notice it ...
) then would the factory 2002 gas damper upgrade do anything, or do I need to look at combined springs / dampers combination to ensure restriction on the travel and subsequently the necessary absorption and avoid scarring the tyre rims ? (bad flash backs of spring stiffness k from undergraduate mech. eng. lectures ...)
If it's the later, then I don't want to kick-off yet another suspension thread - just looking for advice on which way to focus attention.
Cheers,
Lee.
Scene Setting - Required Intro
Problem below is neither due to cramming 4 in the Cerb or trying for Vmax through every countryside lane ... By self classification, I'm hardly a great driver living for every corner - just pootling around enjoying the burbles is enough for me.
Intro Complete
Cerb's running on 18" rims. Basically, I find that whenever out on some seriously undulating roads (generally B's, although it still does happen on the M6), I'll bottom out against the rear tyres a couple of times throughout the journey. Infact, it's now got to the point that I brace in expectation for most troughs in the road to be accompanied with the now familiar aroma of burning rubber ...
Tyre rim wear is even i.e. suggesting that both rear springs are being compressed equally and this is caused simply by the wheels being too big within the arches.
My thoughts are now as follows - will upgraded suspension help this in anyway ? Or, are 18's just simply a bit too big and it doesn't matter what lb'age springs are fitted on the rear, this is still going to occur ... ?
If we reckon that an upgrade is worthwhile (not just based purely for handling reasons - see intro - doubt I would notice it ...
) then would the factory 2002 gas damper upgrade do anything, or do I need to look at combined springs / dampers combination to ensure restriction on the travel and subsequently the necessary absorption and avoid scarring the tyre rims ? (bad flash backs of spring stiffness k from undergraduate mech. eng. lectures ...) If it's the later, then I don't want to kick-off yet another suspension thread - just looking for advice on which way to focus attention.
Cheers,
Lee.
i had exactly the same problem when i first got my cerb,and it happened often too,
first thing was got joolz to alter the camber(is that right?)on the rear wheels,effectively pushing the top of the wheel in which helped.
then more recently a full set of nitrons has helped even more because you can run stiffer springs without ruining the ride quality 'cos the dampers are so good.
i also run my car quite low and its still ok.
mike.
first thing was got joolz to alter the camber(is that right?)on the rear wheels,effectively pushing the top of the wheel in which helped.
then more recently a full set of nitrons has helped even more because you can run stiffer springs without ruining the ride quality 'cos the dampers are so good.
i also run my car quite low and its still ok.
mike.
Use 35 profile on front 40 on rear, have nitron suspension fited and if you have spiders use fronts all round. The rear spiders have a larger spacers behind the hub. Or you could have the back of the arches shaved. This is quite a common problem on 18"
After all is said and done i would go for nitrons as they will 1/ Stop tyre rub. 2/ Much better ride when set up. IMHO...
Mark....
When ou get a chance have a look at the rear wheels behind the hub of the wheel you will see 4 spacers these are actually cast onto the wheel itself. See if the tyre protrudes outside the arch if so all you need to do is either shave the arches or get the spacers removed.
>> Edited by YI8TVR on Thursday 9th October 08:28
After all is said and done i would go for nitrons as they will 1/ Stop tyre rub. 2/ Much better ride when set up. IMHO...
Mark....
When ou get a chance have a look at the rear wheels behind the hub of the wheel you will see 4 spacers these are actually cast onto the wheel itself. See if the tyre protrudes outside the arch if so all you need to do is either shave the arches or get the spacers removed.
>> Edited by YI8TVR on Thursday 9th October 08:28
Are the rear wheels the tuscan rears or the tuscan fronts (it that makes any sense) ?
The fronts have a different offsets from the tuscan 18" rears. You should have 4 front wheels or alternatively have the wheel arches shaved.
All above assumes the suspension is in good condition/set up correctly.
The fronts have a different offsets from the tuscan 18" rears. You should have 4 front wheels or alternatively have the wheel arches shaved.
All above assumes the suspension is in good condition/set up correctly.
First of all thanks guys ! With my 24k service next month, recommendations for Nitrons will mean further focus on the "wage slave" objectives for a few months ... 
alans - running a /40 profile on the rear tyres (standard set-up AFAIK).
Y18TVR - Thanks - going to check the spacers - sounds as though that could be the most straight forward route. Car is actually parked with ABZ_7001 whilst I'm over in Frankfurt (cheers Stu - don't think that it was just the pub lunch on Sunday that's to blame for this one ...
). Therefore, I'll crawl under it next weekend when I'm back in the UK !
However, do we think that the rear springs have softened equally over time ... ? Upon no real basis, I would imagine that this would be assymetric ('99 Cerb - therefore 4 years to do so). I'm holding out that I simply need to create more space in the rear arches.
However, was still interested in what effect the factory damper enhancements would have on spring compression - related in any measurable way ? Or is this my misunderstanding.
Again thanks !
Lee.
alans - running a /40 profile on the rear tyres (standard set-up AFAIK).
Y18TVR - Thanks - going to check the spacers - sounds as though that could be the most straight forward route. Car is actually parked with ABZ_7001 whilst I'm over in Frankfurt (cheers Stu - don't think that it was just the pub lunch on Sunday that's to blame for this one ...
). Therefore, I'll crawl under it next weekend when I'm back in the UK ! However, do we think that the rear springs have softened equally over time ... ? Upon no real basis, I would imagine that this would be assymetric ('99 Cerb - therefore 4 years to do so). I'm holding out that I simply need to create more space in the rear arches.
However, was still interested in what effect the factory damper enhancements would have on spring compression - related in any measurable way ? Or is this my misunderstanding.
Again thanks !
Lee.
I had this exact problem, and I ended up having it sorted at walldonway. They explained that no amount of setting up would sort the problem. My camber was wound right in with inside tyre wear so they were probably right. They said most people got round this by putting front wheels on the rear.
Apparently moulds from old Cerbs have a 20mm wheel arch thickness, while the later ones have 10mm. Verified this while walking round a recent Cerb meet. Mines a 2000 and had 20mm.
If you hoist your car up and move the wheel without the spring on you will see that the side of the tyre hits easily on a 20 but never on a ten. As the tyre rises higher it is actually pulled away from the arch so you never hit once you manage to pass it.
They shaved mine down to ten and reset the camber back to even tyre wear. Now the car never bumps and feels best at the back on handling as well.
Sometimes it really is the simple stuff.
And the best part is that they did it for free while the car was in for other repairs.
Apparently moulds from old Cerbs have a 20mm wheel arch thickness, while the later ones have 10mm. Verified this while walking round a recent Cerb meet. Mines a 2000 and had 20mm.
If you hoist your car up and move the wheel without the spring on you will see that the side of the tyre hits easily on a 20 but never on a ten. As the tyre rises higher it is actually pulled away from the arch so you never hit once you manage to pass it.
They shaved mine down to ten and reset the camber back to even tyre wear. Now the car never bumps and feels best at the back on handling as well
. Sometimes it really is the simple stuff.
And the best part is that they did it for free while the car was in for other repairs.
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