Roll Centre Kits - Honest reviews

[neil a]

Ive had the Northloop kit and the ACS in the past and the Northloop kit was much better quality.

I know of at least 3 cars that have had the bottom pin snap on the ACS kits while on track.

 

[Eddie555]

Was it a ACS kit?

What brand was Ilyas that failed?

@RuskiWeldShit (Ilya) kit was an ACS kit that failed at Anglesey.. He still has an upgraded ACS kit and has been problem free since..

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[Tomotek]

@RuskiWeldShit (Ilya) kit was an ACS kit that failed at Anglesey.. He still has an upgraded ACS kit and has been problem free since..

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Ive had the Northloop kit and the ACS in the past and the Northloop kit was much better quality.

I know of at least 3 cars that have had the bottom pin snap on the ACS kits while on track.

I know the first batch of the lower pins from ACS were made from stainless steel 304 or 316 (chosen for corrosion) which is what caused the failures as the UTS and fatigue properties of the material is far lower than the high strength steel used on most other kits... Anthony did replace people’s broken ones with the high strength steel ones , Ilya included, hence no issues now I believe..

 

[Tomotek]

@neil a .. sounds like you need a PRO-AM geo kit to complete the set too haha

 

[neil a]

@neil a .. sounds like you need a PRO-AM geo kit to complete the set too haha

If I still had a track car I probably would, justnow on my trophy road car its probably not worth it for all the use it gets.

I would say on a standard power track car the rc kit will buy you as much time as a diff on a tight track.
Once you start going up in power and struggle for traction that's where the diff would shine.

 

[Robbie Corbett]

Not sure which kits your referring to that had the potential oval issue.

However we aren’t concerned with the Hubs ovalising on the PRO-AM kit. As long as you fully support the lower surface of the hub with the pin,which it does, then it’s probably got less chance of ovalising the hub than the std pin, even with a lower fulcrum..

When you remove the rubber boot you can see the std lower ball joint pin is only supported by the hole itself.. so all the load wants to try and pry the hole open and closed.

View attachment 1485542

Our kit has a large flange supporting the bottom surface, and the pinch bolt groove to locate the bolt is milled into one side (adding cost but worth it) this allows full face contact 300deg of the pin inside the hub adding more strength and most importantly surface area and durability.

View attachment 1485543
View attachment 1485544
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Tomotek out of professional curiosity and not as criticism, - lovely design. However - as the lower ball joint bracket/holder looks to be machined from solid why didn't you guys add a small top/bottom lip for a rubber boot? If its being machined already its basically free...

Are silicone boots for rose joints available? Would be a simple mould and a useful part if not.

My only other observation with regard to the ovaling comments above - if you are reliant on the extender being up against the pinch bolt face how can you be sure that the cast face is flat and free of annoying casting defects? What steel have you spec'd and what is its fatigue properties? I think realistically you will need to treat the two faces as not being in full contact.

PS I would be happy with either solution over welding anything to a cast hub. Guess the only other potential solution might be to have a slim nut on top of the extender plus the pinch bolt... Not sure how much room there is there though (from memory just enough).

 

[Tomotek]

Tomotek out of professional curiosity and not as criticism, - lovely design. However - as the lower ball joint bracket/holder looks to be machined from solid why didn't you guys add a small top/bottom lip for a rubber boot? If its being machined already its basically free...

Are silicone boots for rose joints available? Would be a simple mould and a useful part if not.

My only other observation with regard to the ovaling comments above - if you are reliant on the extender being up against the pinch bolt face how can you be sure that the cast face is flat and free of annoying casting defects? What steel have you spec'd and what is its fatigue properties? I think realistically you will need to treat the two faces as not being in full contact.

PS I would be happy with either solution over welding anything to a cast hub. Guess the only other potential solution might be to have a slim nut on top of the extender plus the pinch bolt... Not sure how much room there is there though (from memory just enough).

View attachment 1486218

Hi Rob, all points noted, not taken in a bad way at all ... my thoughts below:

1: Rubber Boots - OEM ball joints more often than not are a steel on steel type for cost which are very sensitive to dirt ingress into the joint, as dirt can get between the two surfaces and start to wear it away causing play.. made cheaply needing more protection

We are using motorsport grade spherical bearings (x8 the price) with high precision PTFE liners.. The PTFE liner is a much tighter fit to the inner ball and it’s other function is the edges clean the ball face during articulation, so no boot is really needed.. They are also Stainless steel so don’t need protection for the elements to stop rust... That’s why you never see rubber boots on any wishbones, or Track rod ends on GT or Rally cars etc.. yes they do get cleaned more regularly.. but they are used in much harsher environments and for up to 24hrs straight etc.

2. we state in our build guide to ensure that surface is cleaned properly, and free from rust and defects... however realistically the extender doesn’t need to be in full contact, even if it’s point contacts around the circumference it is far better than the std OEM design.. or if there was a 0.2mm gap it only needs to flex less than 0.5deg before the extender face contacts and offers full support... (looking at some bad examples of ovalising, the OEM pin must have articulated about 10deg!) We also measured lotsss of hubs to make sure we got the right dimensions.. We use EN24-T which is then Zinc plated and de embrittled

3. Yeah a nut would be a nice addition, which we looked into, on the top side, however there is no room between the hub and the ABS ring on the outboard CV joint of the driveshaft.. only about 2mm between the ABS ring and Hub itself, hence why our extender is flush at the top, as per OEM position.

And yeah I’m fully with you on the not welding to the cast hub!, it’s a pain!, and the HAZ effects in the extender would weaken the material properties locally to the highest loaded point, which isn’t good.

 

[Robbie Corbett]

Hi Rob, all points noted, not taken in a bad way at all ... my thoughts below:

1: Rubber Boots - OEM ball joints more often than not are a steel on steel type for cost which are very sensitive to dirt ingress into the joint, as dirt can get between the two surfaces and start to wear it away causing play.. made cheaply needing more protection

We are using motorsport grade spherical bearings (x8 the price) with high precision PTFE liners.. The PTFE liner is a much tighter fit to the inner ball and it’s other function is the edges clean the ball face during articulation, so no boot is really needed.. They are also Stainless steel so don’t need protection for the elements to stop rust... That’s why you never see rubber boots on any wishbones, or Track rod ends on GT or Rally cars etc.. yes they do get cleaned more regularly.. but they are used in much harsher environments and for up to 24hrs straight etc.

2. we state in our build guide to ensure that surface is cleaned properly, and free from rust and defects... however realistically the extender doesn’t need to be in full contact, even if it’s point contacts around the circumference it is far better than the std OEM design.. or if there was a 0.2mm gap it only needs to flex less than 0.5deg before the extender face contacts and offers full support... (looking at some bad examples of ovalising, the OEM pin must have articulated about 10deg!) We also measured lotsss of hubs to make sure we got the right dimensions.. We use EN24-T which is then Zinc plated and de embrittled

3. Yeah a nut would be a nice addition, which we looked into, on the top side, however there is no room between the hub and the ABS ring on the outboard CV joint of the driveshaft.. only about 2mm between the ABS ring and Hub itself, hence why our extender is flush at the top, as per OEM position.

And yeah I’m fully with you on the not welding to the cast hub!, it’s a pain!, and the HAZ effects in the extender would weaken the material properties locally to the highest loaded point, which isn’t good.

Hi Tom?

Nice reply - I am always really interested in the thought process behind design features. Yours seem well reasoned.

1. Sounds good, the pessimist in me still doesn't like open joints thought, cnc machines often have PTFE wipers yet without covers they still wear. Common failure mode for motorbike forks is a stone chip to the stanchions plating, so its really nice to see that the ball joint is stainless and not chrome plated. My feeling is that slight wear the PTFE liner would result in rapid accelerated wear as more and more grime gets into the joint - I see this with robotic actuators where I like to use Igus leadscrew/ptfe nut systems - I can't effectively cover these up due to space. Guessing a joint with boot and ptfe lube would probably last for ever by the sound of it! But appreciate your reasons and I'm sure you carefully considered it during design.

2. Nice - you've clearly thought about it well. For severe ovaling I would suspect the clamp joint is not done up properly, clamp joints aren't perfect, they are not in 100% circumferential contact with the pin (unless the clamp i super funky!) so I guess you could argue there might be the chance of very slight rock - for similar applications in other fields I have used Loctite 648 or 638 with very good success.

3. Ahhh

Cheers for the replies dude, not that you need any validation from others but I think it looks like a lovely, well thought out/engineered kit - and as said before my questions were not criticism of the design (which clearly works well) just curiosity over some of your design decisions.

All the best
Rob,

 

[Tomotek]

Hi Tom?

Nice reply - I am always really interested in the thought process behind design features. Yours seem well reasoned.

1. Sounds good, the pessimist in me still doesn't like open joints thought, cnc machines often have PTFE wipers yet without covers they still wear. Common failure mode for motorbike forks is a stone chip to the stanchions plating, so its really nice to see that the ball joint is stainless and not chrome plated. My feeling is that slight wear the PTFE liner would result in rapid accelerated wear as more and more grime gets into the joint - I see this with robotic actuators where I like to use Igus leadscrew/ptfe nut systems - I can't effectively cover these up due to space. Guessing a joint with boot and ptfe lube would probably last for ever by the sound of it! But appreciate your reasons and I'm sure you carefully considered it during design.

2. Nice - you've clearly thought about it well. For severe ovaling I would suspect the clamp joint is not done up properly, clamp joints aren't perfect, they are not in 100% circumferential contact with the pin (unless the clamp i super funky!) so I guess you could argue there might be the chance of very slight rock - for similar applications in other fields I have used Loctite 648 or 638 with very good success.

3. Ahhh

Cheers for the replies dude, not that you need any validation from others but I think it looks like a lovely, well thought out/engineered kit - and as said before my questions were not criticism of the design (which clearly works well) just curiosity over some of your design decisions.

All the best
Rob,

Hi Tom?

Nice reply - I am always really interested in the thought process behind design features. Yours seem well reasoned.

1. Sounds good, the pessimist in me still doesn't like open joints thought, cnc machines often have PTFE wipers yet without covers they still wear. Common failure mode for motorbike forks is a stone chip to the stanchions plating, so its really nice to see that the ball joint is stainless and not chrome plated. My feeling is that slight wear the PTFE liner would result in rapid accelerated wear as more and more grime gets into the joint - I see this with robotic actuators where I like to use Igus leadscrew/ptfe nut systems - I can't effectively cover these up due to space. Guessing a joint with boot and ptfe lube would probably last for ever by the sound of it! But appreciate your reasons and I'm sure you carefully considered it during design.

2. Nice - you've clearly thought about it well. For severe ovaling I would suspect the clamp joint is not done up properly, clamp joints aren't perfect, they are not in 100% circumferential contact with the pin (unless the clamp i super funky!) so I guess you could argue there might be the chance of very slight rock - for similar applications in other fields I have used Loctite 648 or 638 with very good success.

3. Ahhh

Cheers for the replies dude, not that you need any validation from others but I think it looks like a lovely, well thought out/engineered kit - and as said before my questions were not criticism of the design (which clearly works well) just curiosity over some of your design decisions.

All the best
Rob,

It’s actually Scott .. my surname is Thompson and used to get called Tomo, so was going to use TomoTek as an engineering name lol.. everyone thinks Tom tho

Thanks Rob, no worries, it’s good to pass on knowledge and opinions as it can generate ideas and invoke thoughts that you may not have otherwise had etc.

I defo agree on the clamp bolt!.. very key it’s done up properly and remains tight.. as soon as it comes loose on the OEM it’s asking for trouble.. that’s why we only use K-Nuts on all crtitical joints in our kits.. cost a small fortune but worth it haha!


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[Robbie Corbett]

Absolutely, all the best of luck with it Scott!

Rob

 

[Nathan105e]

I also have a NLC kit from Mark. My setup is BC DS 10kg front, 8kg rear, lowered 35mm from std all round. PMS front strut & RARB, Gripper. Where it made the most difference is in corners with quick direction changes or tightening lines, think chicanes or McLaren/Clearways at Brands Indy, the car would roll and then spring back continuously creating a kind of pogo effect - strange. Once I added the RC kit this was completely gone and the car was so much more stable at low speed. Fitting is easy, maintenance is simple, and Mark turned em around quick. If the kit Tomo is doing is half as nice as the rest of his build then I'm sure the same could be said about his and I do like how they are adjustable to suit different ride heights.

Sorry to jump in on an older post.

Did you use the PureMotorsport top mounts to keep the Strut brace?
Looking at ordering the same coilovers but unsure whether to reuse my PMS stuff or use the new solid top mounts that come with the Coilovers with adjustable caster?

 

[Hollidog]

Sorry to jump in on an older post.

Did you use the PureMotorsport top mounts to keep the Strut brace?
Looking at ordering the same coilovers but unsure whether to reuse my PMS stuff or use the new solid top mounts that come with the Coilovers with adjustable caster?

Sorry to get to this two years later.. Initially yes, but I have now changed to the BC top mounts to get more caster and ditched the front strut brace to soften the front for less understeer. Hope that still helps!

 

[Nathan105e]

Sorry to get to this two years later.. Initially yes, but I have now changed to the BC top mounts to get more caster and ditched the front strut brace to soften the front for less understeer. Hope that still helps!

I went for exactly the same as you in the end, and absolutely love it, had a much better day at Oulton last time i went!

 

[incy-spider]

Sorry to get to this two years later.. Initially yes, but I have now changed to the BC top mounts to get more caster and ditched the front strut brace to soften the front for less understeer. Hope that still helps!

A strut brace can cause under steer? I’d imagine by increasing the caster angle you’ve reduced understeer?

 

[Hollidog]

A strut brace can cause under steer? I’d imagine by increasing the caster angle you’ve reduced understeer?

In theory, yes. Making the front stiffer would increase understeer. I haven't noticed any detriment since doing it, but I did solid bush the wishbones as well to get to the 5.5deg or so of caster I have now. Wishbones were also stiffened and had the ball joint relocated.

 

[Krarl]

I should probably update here since I started this thread but never gave an answer.

I ended up picking up a set of @NorthloopCup / Bridgecraft Engineering hubs. The first word that springs to mind is 'beefy'. Well designed, thought through and look like they'd survive Hiroshima twice over.

I upgraded a lot of things at once, one of them being the hubs and a quiafe diff. The car is 1000x more predictable now, no more bouncing around correcting the steering around corners and you can just point it and tell it where to go. It no longer feels boat like and feels so much flatter going around a corner even with cup shocks and Grams springs. With coilovers I think it'd be perfect for track

 

[incy-spider]

In theory, yes. Making the front stiffer would increase understeer. I haven't noticed any detriment since doing it, but I did solid bush the wishbones as well to get to the 5.5deg or so of caster I have now. Wishbones were also stiffened and had the ball joint relocated.

I’d love to get a good amount of caster, have thought about the pure weld in top plates but it’s quite a job

 

[Hollidog]

I’d love to get a good amount of caster, have thought about the pure weld in top plates but it’s quite a job

Yeah I'd like to do that too but the series I race in doesn't permit you to modify the mounting points of the upright. Although tbh you would struggle to get any more caster into it, on 215/50/15s I had to do quite a bit of clearancing to the arch to get them to stop scrubbing. On 205s it should be fine however

 

[JamesBryan]

Yeah I'd like to do that too but the series I race in doesn't permit you to modify the mounting points of the upright. Although tbh you would struggle to get any more caster into it, on 215/50/15s I had to do quite a bit of clearancing to the arch to get them to stop scrubbing. On 205s it should be fine however

Mine scrubs a tiny bit on 205's 😅

How are you getting 215's under 😂

 

[Hollidog]

Mine scrubs a tiny bit on 205's 😅

How are you getting 215's under 😂

Sledgehammer!