Thundercat fork width

[lilredmachine]

Hi there, I know quite a few people have built 400/600 hybrids on here and might have thundercat bits lying around. 

I'm looking for the measurement inner leg to inner leg. I.E if you were to mount just the spindle with the forks in the yokes, the span of the visible portion of spindle. If anyone has one to measure I would massively appreciate it. 

I'm looking at a whole front end (with some adjustment obviously) to potentially slip in to the yokes of my GSX1100F to get a 17 inch front rim and brakes that will actually stop the thing. 

Incidentally if the measurements are close enough, I will also need a thundercat front end if anyone's got one for sale. 😂

[Evilchicken0]

Go with a Suzuki front end a lot of things seem to simply bolt in. I'd look for cartridge forks (like the TCat) but you could go USD and then look at radial brakes. 

Gsxr 1000 k3 are radial 

[lilredmachine]

I know the stem and bearings are the same as the GSXR, the USD forks and yokes bolt in fine. However the forks are over two inches shorter (at least) which causes geometry and ground clearance issues and the parts are also pretty damned expensive these days compared to the ol' T'cat bits. 

I'm also trying to somewhat retain the original look of the bike, just with modern 120/180 17" rubber and with RWUs that don't look out of place and leave the front end dragging along the ground. Not to mention I find radials to be somewhat overkill when the T'cat swap would leave me with blue spots, a caliper that I have never found wanting.

 

[Evilchicken0]

Ok - a better fork would be earlier R6 RWU, these are 43mm using the later blue spots, again the front end would be easier and if they're not quite high enough you could use some FZR400RR 3TJ yolks that crank down 

[Evilchicken0]

Just a caveat - I don't know you steering geometry offsets etc so just be aware that the front swap will probably change the handling.

ThunderAce might also be an idea but the front wheel wont have the speedo drive

[Superdunc]

32 minutes ago, Evilchicken0 said:

Ok - a better fork would be earlier R6 RWU, these are 43mm using the later blue spots, again the front end would be easier and if they're not quite high enough you could use some FZR400RR 3TJ yolks that crank down 

R6 are too short, hence the request for thundercat info.

[Evilchicken0]

How much more do the R6 need ?

[Damnthistinleg]

I think the 5EB R6 forks are getting on for 2 inches shorter than the Thundercat and TRX forks.

The R6 forks are about the shortest I've come across.

[Evilchicken0]

2 hours ago, Damnthistinleg said:

I think the 5EB R6 forks are getting on for 2 inches shorter than the Thundercat and TRX forks.

The R6 forks are about the shortest I've come across.

3tj forks are about 2" shorter than R6 ... which is why I said the maybe use the 3tj top yoke 

[Mark/Foggy]

Bolt in solution if you want RWU is probably Triumph.  Decent length, cause 955  and Daytona frames go over the top of the engine. Most Triumph parts seem to be to Suzuki style dims.

Brake calipers for them are not so bad and the fork internals are good.

Also not expensive.

Stanchion size is 45mm as well so will be a lot stiffer than T/Cat which are 42. 

Edited May 8, 2020 by Mark/Foggy

[Mark/Foggy]

https://www.ebay.co.uk/itm/Triumph-955-955i-Daytona-Speed-Triple-2005-Front-Forks-2003/274272311330?hash=item3fdbe75822:g:AVMAAOSw7Uhd9AMZ

https://www.ebay.co.uk/itm/TRIUMPH-DAYTONA-T595-955i-OEM-BOTTOM-YOKE-FORK-LEG-TRIPLE-CLAMP-1997-1998/382870450348?hash=item5924db70ac:g:~wUAAOSwM1FcngRe

https://www.ebay.co.uk/itm/Triumph-Daytona-T-595-1997-1998-Front-Calipers/222896962444?hash=item33e5b1bb8c:g:rmMAAOSwUUxatoH0

Edited May 8, 2020 by Mark/Foggy

[lilredmachine]

Thanks for the input guys, I hadn't considered Triumph bits. I know they are more akin to early suzuki stuff than most. 

My reasoning for T'cat forks is this:

T'cat forks are 41mm, as are the Fj12, diversion, Fazer 6 etc, same as the GSX. They are also long due to the T'cat having top mount clip ons. I have discovered (thanks to Hybrid400) the yoke width fork centre to fork centre of a TRX is 190mm, and so is the Fazer, the T'cat is about 203mm. Both the Fazer and the TRX use a 110 front tyre out of the factory. This follows a pattern for earlier Yamaha stuff, essentially if it had a 110 in the front it was 190mm fork spacing, 120 (T'cat etc.) Tyre was 203ish mm spacing.

The GSX has a fork spacing of 213mm by my measurements, which means I could get away with slamming a set of T'cat forks with stiffer springs and heavier oil in the stock yokes, run 5mm spacers either side of the axle and calipers (not an excessive amount) and bobs you're uncle, solve all my problems without reinventing the wheel. 

With a B12/early GSXR rim in the back I'd have a 120/180 tyre size with decent brakes and better quality forks.

I'm aware that we aren't looking at stellar handling and tarmac tearing performance with this setup, however it's a 30yr old 270kg dry, rough as arseholes bike so I'm not wasting good (and expensive) suspension tech on a hack. I just want more (and cheaper) tyre choice and for it to stop a bit better. Basically, there ain't nothing wrong with the-essentially-a-gixxer lump in it. So it has far more poke than the marginal-when-new brakes are comfortable dealing with. 😂

Edited May 8, 2020 by lilredmachine

[lilredmachine]

This is a set of T'cat forks in a GSX. 

Strange thing is in this case, the bloke went to a huge amount of hassle to keep the standard 16" front wheel, converting the discs and forks to work with the smaller rim. Seems odd. 

Other advantage is the enormous T'cat mudguard really doesn't look out of place on the GSX, which is usually an issue with these sort of swaps, like the one on my modded Diversion. 

[Mark/Foggy]

I would double check the stanchion size if I were you. I did a lot of work looking into them a while ago, but my memory could be playing tricks with me. Classic Endurance was running a max stanchion of 42 and R6 RWU was out of bounds at 43. Andreanni do a kit for Bonneville etc, but that is a single disc stanchion, plus it needs a deep boring mod in the tCat stanchions to get the cartridges to land deep enough.

Thankfully Ohlins got involved and just took the job in house and fitted a custom solution. 

Yes you did read that correctly. 

[Mark/Foggy]

It's an interesting project...this.

I was a DR many moons ago and always wanted one. They just sold so few that I never actually saw one for sale in the right place and at a sensible time. Plus the front tyre issue was always going to be a hassle.

Fine bike if you ever want to go to the moon and back. You could probably just fill the sump with gear oil and not have to think about changing it until you got home.

Don't try this at home folks, probably would only work in zero Gravitas.

[lilredmachine]

18 minutes ago, Mark/Foggy said:

I would double check the stanchion size if I were you. I did a lot of work looking into them a while ago, but my memory could be playing tricks with me. Classic Endurance was running a max stanchion of 42 and R6 RWU was out of bounds at 43. Andreanni do a kit for Bonneville etc, but that is a single disc stanchion, plus it needs a deep boring mod in the tCat stanchions to get the cartridges to land deep enough.

Thankfully Ohlins got involved and just took the job in house and fitted a custom solution. 

Yes you did read that correctly. 

😂 Those crazy Swedes.

Yeah, T'cat forks are 41mm. The only forks I've ever come across that are 42mm are the early model GSX 600/750f forks, it's a really weird size. Incidentally, the early GSX's also have adjustable damping and 4 pot brakes fitted as standard... In 1988, and on a budget bike at that.

If they were 42mm, they wouldn't be in the stock yokes of the Diversion above. 

Edited May 8, 2020 by lilredmachine

[lilredmachine]

2 minutes ago, Mark/Foggy said:

It's an interesting project...this.

I was a DR many moons ago and always wanted one. They just sold so few that I never actually saw one for sale in the right place and at a sensible time. Plus the front tyre issue was always going to be a hassle.

Fine bike if you ever want to go to the moon and back. You could probably just fill the sump with gear oil and not have to think about changing it until you got home.

Don't try this at home folks, probably would only work in zero Gravitas.

Aye, it's a beast of a bike and one that I never thought I'd end up owning. They are relatively rare now, and when they do come up they go for too much money to warrant an 'oooooh' purchase IMO. This one was cheap, needs some work, most of which could be fixed with a front end. 😂

[Mark/Foggy]

Do it, I think the 955i front end would help a lot. Must be any number of subtle things that could make the back work better. Oh and you are aware that they love a turbo.

The ultimate street sleeper. 

'I was staying with him until his panniers flew off, WTF.'

[lilredmachine]

7 minutes ago, Mark/Foggy said:

Do it, I think the 955i front end would help a lot. Must be any number of subtle things that could make the back work better. Oh and you are aware that they love a turbo.

The ultimate street sleeper. 

'I was staying with him until his panniers flew off, WTF.'

In the actual thread of this bike over in readers bikes/projects I have been repeatedly asked to turbo this thing. 

I may break eventually.  

[Mark/Foggy]

Chassis first......Oh and a proper brake upgrade,,,

[Thunderbolt]

8 hours ago, Mark/Foggy said:

I would double check the stanchion size if I were you. I did a lot of work looking into them a while ago, but my memory could be playing tricks with me. Classic Endurance was running a max stanchion of 42 and R6 RWU was out of bounds at 43. Andreanni do a kit for Bonneville etc, but that is a single disc stanchion, plus it needs a deep boring mod in the tCat stanchions to get the cartridges to land deep enough.

Thankfully Ohlins got involved and just took the job in house and fitted a custom solution. 

Yes you did read that correctly. 

Did classic endurance run a max of 42 as an Italian manufacturer made 41.7mm forks?

[Mark/Foggy]

Yes, though the regs may have moved on a bit now, depending on class. 

Marzocchi MR1 are sort of the holy grail. 

 

[Superdunc]

You can run 43mm forks in classic Endurance now. 

 

[Mark/Foggy]

That helps

[Evilchicken0]

I thought TRX and FZR600R Foxeye ran 3.5" front wheel with a 120 tyre. 

[Thunderbolt]

22 hours ago, Mark/Foggy said:

Yes, though the regs may have moved on a bit now, depending on class. 

Marzocchi MR1 are sort of the holy grail. 

 

That’s what I guessed.

[lilredmachine]

On 5/9/2020 at 10:17 PM, Evilchicken0 said:

I thought TRX and FZR600R Foxeye ran 3.5" front wheel with a 120 tyre. 

TRX is (or supposed to be) 120 but is a 60 section which I was incorrect on, but I was also referring to the Fazer 600 MK1 which was indeed a 110 on the front. 

The Foxeye was also a 60 section on the front. I'm guessing that a stunted sidewall height also makes the tyre overall narrower compared to a larger sidewall height. 

My Bandit is a 180/55 stock but cannot fit a 180/60 in due to the added width the higher sidewall height adds. It's really annoying considering the access I have to cheap, barely used sticky race scrubs in that size. 

[Kayla]

On 5/8/2020 at 11:03 PM, lilredmachine said:

T'cat forks are 41mm, as are the Fj12, diversion, Fazer 6 etc, same as the GSX. They are also long due to the T'cat having top mount clip ons. I have discovered (thanks to Hybrid400) the yoke width fork centre to fork centre of a TRX is 190mm, and so is the Fazer, the T'cat is about 203mm. Both the Fazer and the TRX use a 110 front tyre out of the factory. This follows a pattern for earlier Yamaha stuff, essentially if it had a 110 in the front it was 190mm fork spacing, 120 (T'cat etc.) Tyre was 203ish mm spacing.

TRX, Thundercat and FZR600R all use the same geometry yokes- 200 pitch and 30mm offset and are interchangeable as are the forks but you'll need a couple of small spacers to use the TRX/FZR6R wheel in Thundercat forks. The brake stuff all lines up nicely though and they all use a 17mm spindle  The TRX bottom yoke is aluminium and nicer if you can find one. TRX has a 120 front tyre as standard on a 3.5" wheel, OG Fazer 6 is 110 on a 3" wheel. FZR400 3TJ, FZR600R and TRX front wheels are the same part and all came with a 120/60 tyre as standard.

Late FZR6R forks are fully adjustable like Thundercat forks.

On 5/9/2020 at 10:17 PM, Evilchicken0 said:

I thought TRX and FZR600R Foxeye ran 3.5" front wheel with a 120 tyre. 

They do

[Damnthistinleg]

I will have an entire standard front end that will be coming off my TRX quite soon.

I've ran a 120/70 on that for years and it's been fine with the taller profile, if a little slow steering (but then they all are). You'd want some much stronger springs in there if you were to use TRX bits on that behemoth though. Mine is at 169kg but still bottoms out like a bastard when braking hard.

I'd look at Triumph front ends if I was doing it. They're not bad on the road and you still get excellent calipers with the Triumph/Nissins.

[Superdunc]

19 hours ago, lilredmachine said:

TRX is (or supposed to be) 120 but is a 60 section which I was incorrect on, but I was also referring to the Fazer 600 MK1 which was indeed a 110 on the front. 

The Foxeye was also a 60 section on the front. I'm guessing that a stunted sidewall height also makes the tyre overall narrower compared to a larger sidewall height. 

My Bandit is a 180/55 stock but cannot fit a 180/60 in due to the added width the higher sidewall height adds. It's really annoying considering the access I have to cheap, barely used sticky race scrubs in that size. 

I run 180/60 on all my oil boilers, though I guess you run a 530 chain for the turbot.