Plus two brakes with bolt-on hubs

[RotoFlexible]

I am not clear on how (or whether) I can fit plus two brakes to my bolt-on S2. I bought used calipers, rotors, and mounting brackets in good condition. On attempting a trial fit this morning, I found that the rotor fouls the tie rod end. If I recall correctly, this works without difficulty for knock-on hubs but apparently it doesn't work with the smaller spindle used with the bolt-on hubs.

Is there a way to make this work? My guess is that even if I fit the larger knock-on spindles (and the vertical links they require), my hubs won't work with the spindles, since the bearings are larger. Even if they do, the track will increase slightly (which I can't afford).

Is there any reasonable way forward? If not, I will be offering a good set of Plus Two brakes for sale.

Executive Summary (if you don't want to read through the thread): The +2 brakes do work with the smaller bolt-on spindles and hub. The interference problem was due to a misshapen tie rod end and was rectified with a file. When rebuilding +2 brakes, make sure to get the correct pistons and seals for your earlier (16P) or later (16PB) calipers - check the +2 parts manual for illustrations.

[gino1]

Hi,
Your assumption is correct, all you nmention is correct ...how much for the calipers?
I have fit the bigger +2 brakes and calipers on my S3 with knock ons.. Was quite straight forward and needed only to change the caliper mounting brackets and grind some of the caliper away as it was fouling on the inside of the wheel.
The difference is quite noticeable.
Gino
s3 Coup? '65
s3 Coup? '67
+2 '69

[RotoFlexible]

Let me float an idea. The Triumph GT6 uses bolt-on wheels. Since the Plus Two (and knock-on 2-seater) vertical links and spindles are from the GT6, it stands to reason that GT6 hubs (and rotors) should work with Plus Two links and spindles.

I checked a couple of sites that sell GT6 parts. They don't show the hub as an orderable part (although the Spitfire hub can be ordered). There are "GT6 hubs" available on ebay, but they are listed as fitting both GT6 and Spitfire, which makes me nervous.

Anyone have experience (or even an educated guess) using GT6 bolt-on hubs on an Elan?

[paddy]

My understanding is as follows:

- Triumph fitted two sizes of stub axle and bearing; a smaller one on the Herald and Spitfire, and a larger one on GT6 and Vitesse;

- the bolt-on arrangement on early Elans correspond to the Herald/Spitfire arrangement, and bearings and hubs are interchangeable with these;

- the knock-on hubs fitted to later Elans and +2s used the larger arrangement, so the bearings are interoperable with the Vitesse and GT6.

I believe that if you have an original Elan upright and bolt-on hubs, then you need Spitfire/Herald hubs and not GT6. You can fit GT6 bolt-on hubs if you switch to uprights from a "knock-on" car.

I did recently compare a GT6 hub and an Elan bolt-on hub. Although I didn't make reliable precise measurements, it did look like the only material difference was the bearing/stub axle diameter.

(I said material difference - the Elan hubs were a very early Herald/Spit hub which had a very shallow boss (where the grease cap fits) whereas the later Spit and GT6 hubs had a deeper boss to help locate the wheel.)

Paddy

[cabc26b]

Hi Russ,

You will need to use all GT6 pieces to pull it off. start with the upright, then get the big axle - I have use this set up a lot - see pictures all based off the gt6 upright and larger axle -

Hope this helps

G

[RotoFlexible]

George, Paddy - thanks. Just what I need to know.

[RotoFlexible]

Well, I'm now the proud owner of spindles, vertical links and hubs from a GT6 that is being parted out locally. Once my car is down for the winter, I'll fit everything up and report back.

[RotoFlexible]

I pulled a hub from my car and put it next to the GT6 hub. Measurement confirmed my eyeball appraisal: the GT6 hub puts the wheel 1/4" further from the spindle than the original hub. This is probably not a big deal for the steering geometry, but it is a big deal for clearance. One tire is already nicking the edge of the opening under unusual combinations of jounce and steering angle.

I don't think that cutting 1/4" from the wheel mounting face of the hubs is an option. Unless someone has a suggestion (that doesn't involve flairs), I think this project is dead.

[paddy]

I don't think that cutting 1/4" from the wheel mounting face of the hubs is an option. Unless someone has a suggestion (that doesn't involve flairs), I think this project is dead.

Go back to your original hubs (or alloy equivalents) and machine 1/4" from the face that the disc mounts to?

Paddy

[ncm]

Can you not space the steering arms away from the disc on your original set up?

Brian.

[RotoFlexible]

I don't think that cutting 1/4" from the wheel mounting face of the hubs is an option. Unless someone has a suggestion (that doesn't involve flairs), I think this project is dead.

Go back to your original hubs (or alloy equivalents) and machine 1/4" from the face that the disc mounts to?

Paddy

Hmmm. It wouldn't necessarily be 1/4", but rather the amount needed to align the disk with the caliper, whatever that is. I'd need to do some careful measurement, but yes, in theory that would work. I'd rather do it on a second set of hubs, though!

Thanks for the suggestion.

[miked]

Andrew,

Are the Canley classic (Triumph site) alloy bolt on hubs not less in depth than the GT6 cast heavy hubs. I have some on a project car but the body is not fitted yet. I have plus two brakes on a baby Elan.

I can measure the depth if you want.

Mike

PS these are for a GT6 as they have the same bearings as a peg drive. They show on the net as a GT6 item alternative, as I recall.

[cabc26b]

Andrew,

Dave bean sell an Alloy hub is dimensionally the same as the small spindle but will take the large bearings and spindle. Those calipers weight quite a bit more than the 12's that came with it.

[miked]

Measured it anyway when in the garage! It is 44.1mm for Canley Classic alloy 4 bolt - GT6 hub.
Did not have a baby Elan peg drive one without pulling a wheel off.

Measured a spare plus two one at 53.3mm. As I recall, is a baby Elan peg drive one about 46mm.

I would only have lost the bit of paper with it on, so there you go!

Mike

[RotoFlexible]

Well, once again I've jumped to a conclusion (and spent money) before getting all the facts. It turns out the interference between the disc and the rod end is due to the thicker +2 disc combined with the suspension being at full droop. (See photo.) When I crank up the suspension closer to ride height, the interference goes away. So, with the +2 rotor mounted to my original bolt-on hub, everything works: the +2 calipers center nicely on the disc, the wheel fits.

Now I just need to get rid of the rub at full droop. I can take an angle grinder to the rod end to radius the sharp top edge, or I can use really good washers to space the steering arms in about 1/16". I prefer not to mess with the geometry, even a little bit, so I will probably try the angle grinder first. (Third possibility: someone may supply tie rod ends with a rounder profile.)