Bushings and circuit use

[Clarkgti]

What are peoples thoughts on the following bushing types that I'm debating for the winter upgrades. Rear needs rebuilding as it's old rubber and front is a mcpherson strut on a fwd car with std rubber so also needs doing.

1. Spherical
2. Hard Race rubber arms/individual bushings
3. Super pro Poly bushes

The front will be either super pro on the wishbone or hard race rubber, not sure how hard this rubber is though.

Rear will either be completely super pro Poly or a mixture of that and hard race rubber/arms.

I mention spherical as I've no experience with these so wondering if people who've used them can clarify if they really are that good? I could possibly stretch budget a little to add a few here and there.

Also anyone who's used hard race rubber on circuit and can confirm if these do suffer deflection similar to an oem rubber bush or not?

[Krikkit]

If you're building a car with that kind of focus, where geometry is critical, then they're well worth the effort.

But it'll be very expensive, need more maintenance, and useless for the road.


As an example - I run a Fiesta track car, and a guy in the group has just developed a set of sphericals for the rear beam. His demo of how much play even low-use powerflex black bushes had vs the spherical (which was obviously 0 movement) was quite eye-opening. His is a proper full-fat race car with slicks though.

[Clarkgti]

Krikkit said:

If you're building a car with that kind of focus, where geometry is critical, then they're well worth the effort.

But it'll be very expensive, need more maintenance, and useless for the road.


As an example - I run a Fiesta track car, and a guy in the group has just developed a set of sphericals for the rear beam. His demo of how much play even low-use powerflex black bushes had vs the spherical (which was obviously 0 movement) was quite eye-opening. His is a proper full-fat race car with slicks though.

It's road legal but only miles are to the track and on road testing so not bothered about road stuff. At some point it will likely be off the road entirely.

Yeah the poly are weird from my understanding they can creep and set and change how the suspension works as they become a bearing of sorts rather than a bushing. Lots of competitive cars in amateur race series run them though so maybe they're good enough.

Spherical every where would be great but with independent suspension on the rear with loads of bushes that would become very very expensive very fast.

Very interested in anyone who has experience of hard race rubber though as it doesn't change how the suspension should operate being still rubber but not sure if they're rubbish at deflection or not.

[Krikkit]

Clarkgti said:

Yeah the poly are weird from my understanding they can creep and set and change how the suspension works as they become a bearing of sorts rather than a bushing. Lots of competitive cars in amateur race series run them though so maybe they're good enough.

Very often they're exactly that - good enough upgrade from standard soggy/tired bushes and great for a control series as everyone's running the same.

Multi-link would get very expensive to replicate, in many cases though on a rear-end you'll get pretty good feel from fairly standard metallastic bushes and new ball joints. Dunno if you have access to a lathe, but you could make your own delrin bushes (if there aren't any off the shelf somewhere) to replace them, it's so easy to do if you have the time/access.

What have you got on the front? McPherson? If so that'd be a good contender for custom spherical bearing and rose-jointed lower arms etc.

Edited by Krikkit on Tuesday 26th July 12:23

[GreenV8S]

I don't know which poly bushes you're looking at but my experience with some of the aftermarket ones is that they're surprisingly soft and don't actually offer great geometry control. YMMV.

Your experience with solid metal-on-metal bushings will depend primarily on how good your dampers are and also how smooth the road surface is. If you use them, make sure you get good quality PTFE lined ones and fit seals over them.

[HustleRussell]

Spherical bearings on a Golf GTI is an engineering project. You are into custom fabricated bushes, wishbones etc to do the conversion. After that you are replacing the bushings quite frequently at not insignificant expense, and re-doing the geometry each time.

The question is what issue are you trying to solve with the car's handling? It's not something you do just 'cos.

[Clarkgti]

HustleRussell said:

Spherical bearings on a Golf GTI is an engineering project. You are into custom fabricated bushes, wishbones etc to do the conversion. After that you are replacing the bushings quite frequently at not insignificant expense, and re-doing the geometry each time.

The question is what issue are you trying to solve with the car's handling? It's not something you do just 'cos.

Verkline and hard race do spherical options for the golf just the sheer cost of them makes me consider will I get that value back.

No it's not just 'cos, deflection is the issue. Especially at the front being a macpherson strut. On top of 90% of the bushes being 14 years old and likely super saggy.