Triumphrat

Slinky · 10-15-2005, 05:05 PM

Can anyone tell me if fitting a TBS front wheel to a normal Thunderbird is straightforward?

Obviously, one front disc would need to be removed, and the other replaced with the Tbird disc. I believe the speedo drive may be different. Any other pitfalls? Thanks.

denny · 10-15-2005, 07:52 PM

If you want the speedo to be accurate you will need a speedo from a legend or TBS.

I've seen a TBird with a TBS rim fitted. The brake disk is a simple bolt on.

The axle spacers will likely need changing.

Talk to cafetbird, He's done it. It's his bike Ive seen with the TBS wheel and only one disk in place.

[ This message was edited by: denny on 2005-10-15 21:40 ]

johnyC · 10-16-2005, 07:33 AM

Slinky,

I'm about to (this week or next) rebuild my TBS wheels. I have an 18" alloy rim and spokes from an early t'bird which I'm building onto the TBS hub. I will then be left over with the single disc type t'bird hub to which I'm lacing the chrome 3.5X17" TBS rim to end up with what you want on the front

I was going to rebuild the rear wheel with a brand new alloy rim I've already bought from Central Wheel co. However, if you're also looking for the 17" TBS rear to go with the rebuilt front, all I'd need from you would be your old t'bird rear in exchange, I'd only need the hub to lace up to the new alloy rim.

I'd rather all this stuff went to one of us on the forum than to someone I don't know on ebay, so get in touch if you want these wheels. I've already offered the front to Jimmy J but he doesn't need it, so you can have first shout, OK?

ps. the only actual cash cost to you would be a contribution to the life boat tin.

Jodel · 10-16-2005, 07:51 AM

Slinky,

I put a TBS front end on my TBird and IIRC the axle and spacers should be fine but the front disk on the TBird is a slightly larger diameter than the TBS - although I think this should be OK as caliper mounting points won't change. The speedo drive on the TBS is on the RHS rather than the LHS so you'll need to source a drive unit. The speedo itself will be fine (mine is). The only other thing that occurs to me is that the front fender mounting bolts on the TBird might end up being in pretty close proximity to a 120 x 17 tyre as it is a smaller diameter (by about 30mm) and wider than the original 110 x 18. The TBS forks have mounting points lower down on the forks.

As you know, the TBS hub is designed for twin disks so it might look a bit 'unfinished' with one missing. If you only want to change to get a 17" rim, it might be easier to source a Legend wheel or have your TBird hub rebuilt with a 17" rim - Hagon can do this at a reasonable cost.

If you want to drop me a PM I can always send you some pics of my conversion which might help make things clearer.

johnyC · 10-16-2005, 08:11 AM

Jodel,

The 3.5X17" on a single disc hub is essentially a legend wheel. It would go straight into Slinky's forks with his ancillaries like spacers, etc without any b#ggering about. The distance between leg centres is the same.

The mudguard and mounts on a t'bird and a legend are the same, so if you put a legend wheel in a t'bird it won't clash with the 'guard.

In my case to fit a t'bird guard to my TBS I have to b#gger about a bit myself, I need to remove the rivets from the TBS guard and fit the blade from a t'bird guard to the longer TBS brackets.

as regards speedo calibration after changing the wheel size? well I'll worry about that later. I may re-calibrate the TBS speedo against an accurate digital bicycle type speedo.

MickMaguire · 10-16-2005, 09:19 AM

I'm a bit late into this but no speedo calibration is required. the Legend, TBS and Tbird all use the same part. I am using my Tbird speedo with my 17" ZRX wheels without any recalibration. To be sure I checked it against a car - I held a steady 50 and got my wife to follow me and check her speedo, it read exactly 50. I beleive that the diffeence between the rolling diameters of the 17 and 18" wheels/ tires is within the tolearnces that they allow on speedos (usually speedos read up to 10% under true speed).

Jodel · 10-16-2005, 12:53 PM

Slinky,

You ask a simple question and look at the trouble you've caused :razz:

Mick, I think the law in the UK states that you can change tyre/wheel sizes if the change results in a difference of less than 2% of the original wheel/tyre size. If my calculations are correct (a big if) the difference between an 110x18 and 120x17 is over 5%. On my fische, the part number for the TBS speedo drive is different to the two listed for the TBird so I assume the internal gearing of the drive unit is slightly different.

JohnyC - Rather than mess around with the rivets on the fender, I just made up a couple of brackets to get the TBird fender to fit the TBS forks I now have. Your way sounds like it might be a bit more elegant - I sense another mod coming on......

BTW: I fitted a Sigma BC1200 bicycle computer (you can get them at Argos) as an 'extra' and can recommend this type. The only snag is that you have to splice in a small additional length of wire between the sensor and the head as it is slightly too short as supplied. Sigma are one of the few computers which can cope with motorcycle speeds.

A lot of the bicycle computers only work up to about 60mph or so - mind you that's more than fast enough really :-D

Slinky · 10-16-2005, 02:50 PM

Wow thanks for the great responses everyone. I think I am a little more confused now than when I started.

I was looking at a TBS front wheel c/w discs & new tyre on ebay, going cheap but then the rim has been powdercoated black. I like the idea of black rims but that would mean having to get my rear stripped & coated to match.

Johnny, thanks for the offer. Let's see if we can work something out- I'll PM you.

denny · 10-16-2005, 10:35 PM

just an fyi mick the TBS speedo reads 0-155 my TBird speedo reads 0-135.
No quite the same part. I don't know about the rolling diameter.

cafetbird · 10-16-2005, 11:28 PM

O.K. - my time to chime in now. The TBS, T-Bird, and Legend speedo units are all different. Other than that, and the need to use a T-Bird 320mm brake disc, a 17" TBS wheel is a direct bolt up to the T-Bird. No need to re-lace the wheel or anything, but you will need to mount it in reverse to use the speedo unit correctly. I would use a Legend speedo over a TBS, because the TBS mounts on the opposite side of the wheel. As Denny sez, I know because I have done it.

One issue you will have to address is the front fender. The T-Bird fender has a curvature for a 18" wheel, and you'll need to get a Legend fender for the swap to look right. The bike will look like a motard-retard with the stock unit.

FYI - on the back, you can use a Tiger rear wheel if you want to swap that out to 17". It is the same as a TBS wheel - but it does have a dull anodized finish on the rim.