Fork Link Bearing Conversion

[steeleyscoot]

Has anyone got experience of doing the fork link needle roller bearing conversion as offered by West Coast Lambretta?

[Warkton Tornado No.1]

No, but more 'conventional' shielded, deep groove ball bearings (smaller versions of what are fitted drive side for the crankshaft) can be fitted. A pair each side with spacer tubes can be fitted. Other than the spacers, if I remember correctly, there are no further engineering modifications.

If you choose this method instead, I can dig out & tell you the relevant information.....Ha! I'll never wise up & make dosh by selling a kit @ extortionate 'dealer prices'

I hope that helps......

[steeleyscoot]

The approach you’ve suggested makes sense, however I’m more attracted to something that’s (hopefully) straightforward to fit and you can buy off the shelf. Also looking at the size of the needle bearings they supply it looks like it would spread the load more evenly. Why a UK dealer doesn’t offer the conversion surprises me, same as the tapered bearing conversion than Ian Frankland used to offer for forks?

[Knowledge]

I have always thought that the fork-link goes through such a small rotation around the pivot that it doesn’t justify the use of a bearing and would be better supported on a bush.

The WCL conversion appears to be a solution looking for a problem.

Can someone please explain why needle rollers are better than a bush?

[Warkton Tornado No.1]

Plain (bush) bearings have a lot going for them, as even with today's modern four stroke engine as used in the majority of car engines, con-rods with shell bearings are still the norm. Plain bearings are not just for scenarios where the amount & rate of rotation are low.

Plain bearings were used for many years in the piston end of the con-rod of two strokes, so they were able to cope with scant lubrication. Needle roller bearings became commonplace @ the point where two stroke development meant looking for reductions in friction & inertia to increase performance.

Similarly, if needle bearings or deep groove ball bearings are used in fork links, they will offer the same advantages. The amount that the fork links work on a typical road surface should not be underestimated. Factor in a Lambretta prepared for track racing, where cornering, acceleration & deceleration will multiply the loads further & it can perhaps be better understood why some riders prefer their use.

However, my belief is that they offer a stiffer assembly due to the accuracy of production. It may be only a tiny improvement, enabling better control of the front wheel, but in any Motorsport, any margins gained all stack up.

[Meds]

There are some dangers here that may need consideration
The impact loads on the fork link bush bearings will be pretty High - considering 100kg of Lambretta and 80kg of rider jiggling up and down at quite a rapid rate. The bush spreads the load across it full length, thus lessening the point loading.
I appreciate that Bushes do wear (part of my regular winter checks) - but I’ve not heard of any failing completely - where as failure or collapse of a bearing is a known problem.
So care should be exercised when specifying what bearings are required.

[Warkton Tornado No.1]

There are some dangers here that may need consideration
The impact loads on the fork link bush bearings will be pretty High - considering 100kg of Lambretta and 80kg of rider jiggling up and down at quite a rapid rate. The bush spreads the load across it full length, thus lessening the point loading.
I appreciate that Bushes do wear (part of my regular winter checks) - but I’ve not heard of any failing completely - where as failure or collapse of a bearing is a known problem.
So care should be exercised when specifying what bearings are required.

I can't vouch for needle bearing conversions. However, I would imagine that the 'Mountain' @ Cadwell Park with it's tendency for riders to demonstrate their ability to wheelie very capably is as much a test that the ball bearing conversions are ever likely to encounter.

The fact that even V*spas achieve the same with their fork link bearings should really offset any concerns IMHO

Sadly, the incidents of rear hub bearings produced by MB (with their asymmetric plastic cages) have done nothing to bolster the reputation of deep groove ball bearings, but I would remind everybody that Lambretta front axles are thus equipped. My reckoning is that they are the first engineered, rotational 'power transmission' component within the front suspension to be subject to load.

Personally, I always source mine from Engineering Suppliers ensuring they are European or Japanese & have never witnessed a failure in close to 50 years. Much the same principle as the chain that I procure, which you may recall being discussed previously.......

[GExS]

Might be a good idea but be careful of West Coast Lambretta, the website is from 2006 ish when is was sold. It’s not a shop, do more homework.

[Andy B.L.C.]

Used to race against West Coast Lambretta when I was escaping the poll tax (how much would that garage load of crap be worth now...?!)

Explanation. Worked @ the SF scooter center & was a team Lucky 7 race spanner monkey, fun times...

Since Vince is no longer part of the deal, I imagine reliability is a bit like our own up noorf used to be...

[corrado]

Why a UK dealer doesn’t offer the conversion surprises me, same as the tapered bearing conversion than Ian Frankland used to offer for forks?

Ian also made a fork link bearing conversion.

[Toot]

Has anyone got experience of doing the fork link needle roller bearing conversion as offered by West Coast Lambretta?

Hi Dave

I've been running these skateboard bearings in my SX forks for 10 years now (over 30,000 miles). Absolutely no issues experienced. I seem to recall it was a very easy job to fit them.

Quite a few of our riding group have also had this conversion done over the years.

I can't comment how this compares with a non-bearing conversion lambretta as I've never ridden anyone else's lambretta in anger.

Toot

[Wee Mark]

Any more info on this conversion please Toot?

[Toot]

Any more info on this conversion please Toot?

I'll dig the spare set of bearings out and this should job my memory

[jonoy]

What parts do you need for this conversion

[gp200ts1]

My series 2 runs bearings instead of bushes. Ian Frankland gave me his drawings of how to do it with 2 sealed bearings, a spacer tube and 2 20 thou shims for each link. Been in there 4 or 5 years and done thousands of miles. As easy to fit as pressing in the bushes and had no problems with wear whatsoever.

[jonoy]

I’ve tried 2 different nylon inserts but the steel inserts will
only fit by pressing in and as I understand it that’s too tight.
Don’t have the facilities to ream the nylon bush so looking for alternative.

[ULC Soulagent]

I bought a pair of tv175 links for my production scoot which had the bearings fitted but Harry @ Pro Port removed them as he showed me they locked up under pressure when everything was tightened up so reverted back to mb setup