GT550 front rim

kmil · Post by **kmil** » Thu Jan 15, 2009 7:31 pm

Hi all,
I have a GT380 front fork assembly that I need a new wheel to complete. I have a GT550 front wheel with disk but it looks like it might be to wide. My question: is a GT550 front wheel wider that a GT380 wheel and will it fit on the GT380 front assembly? Any help would be great.

kmil

Coyote · Post by **Coyote** » Thu Jan 15, 2009 8:08 pm

Part numbers are the same for the 380 and 550. Should bolt right up -- no problem.

rngdng · Post by **rngdng** » Fri Jan 16, 2009 8:50 am

Coyote wrote:Part numbers are the same for the 380 and 550. Should bolt right up -- no problem.

Also the same as GT750 and GT500. I have a couple of decent front wheels.

Lane

H2RICK · Post by **H2RICK** » Fri Jan 16, 2009 1:02 pm

I'd be careful, gents.
The 380 used a 1.60 wide rim on the front with a 3.00 x 19 tire whereas the 550/750 used a 1.85 wide rim with a 3.25 x 19 tire.
The rim part numbers are definitely different.
That's why he's saying that the 550 tire looks too big.
The hubs ARE the same but that's ALL that's the same.
Now some guys will tell you that the wider tire doesn't matter all that much....
but it WILL slow the handling down somewhat.

rngdng · Post by **rngdng** » Fri Jan 16, 2009 1:52 pm

Oh, OK. I believe you. I think my extra wheels all came from 750s. I'll have to look.

Lane

tz375 · Post by **tz375** » Fri Jan 16, 2009 5:24 pm

1.60 is really narrow by any measure. Fine for an 80 but a little on the narrow side for a 380.

I would think that a 1.85 would be fine in that application without the steering becoming noticeably heavier.

But that's pure hypothesis on my part since I haven't tried it.

kmil · Post by **kmil** » Fri Jan 16, 2009 7:50 pm

Thanks for the answers guys. I took my trusty measuring device out and measured the rim, it is a 1.85. I also tried to mount the bare rim on the 380 front end and the disk rotor is way to large in diameter. With the tire on the rim it will be a tight fit. I took the smaller diameter disk rotor off a gs450 mag wheel and the wheel with rotor fits nicely. Looks like it might work if it doesn't spread the front tire (90/90-19) out to wide. I guess I will find out. Mixing and matching sure is fun. Thanks again.

Coyote · Post by **Coyote** » Fri Jan 23, 2009 3:42 pm

Also overlooked are the spokes. The GT550 rear spokes are 3mm stem diameter. The GT750 rear spokes are larger at 3.5mm. That's why the spoke part numbers are different. Fronts are the same.

1975 GT550 rear: 65300-31831
1975 GT750 rear: 65300-45811