Modern Vespa

I bought what appears to be a theft recovery 2008 GTS250. I've been going through all of the problems trying to get it roadworthy, here's the last.

It was clear the front wheel was bent. Riding it had a huge wobble and spinning it in the air when mounted on the hub it had about 10mm of runout at the rim. It had impact damage clearly, looks like it probably hit a curb real hard. Scooter's been down sometime long ago with bent bodywork on the same side as the curb impact. So I bought a new front wheel and had the tire switched over.

Now it still has a little bit of runout and the rotor scrapes when you spin it. I took apart the spindle and bearings, repacked everything, reset it. Still has a little bit of runout.

Is it likely the hub is bent? Part #50 in the diagram. Can that part be straightened? Or would you trust a used part? New one is kind of expensive.

If it's not the hub, maybe part #2 in this diagram may be bent:


SW shows out of stock for the part. Is this a thing? Seems like if it was bent it wouldn't cause the wheel to have a wobble/runout in it, but it'd run straight, just not square with the fork.

Thx-

I'm just throwing some ideas out there so take it for what it's worth.

It sounds like you swapped over the old tire. There may be a chance it is deformed from sitting after the theft & recovery. Did you check the front brake disk on a flat surface to see if it is warped/bent? If the old wheel took a blow hard enough to bend it. Then who knows what else may have been damaged while absorbing all of that energy? Does the scooter track straight? Check the frame spine for popped welds and buckling. Check for a bent steering column & fork assembly. I think the front cast alloy hub would crack before it bends, no? It's hard to judge for slight bends in parts just by eyeballing them.

Good luck sorting it out.

if the wheel took enough of a hit to bend, it's likely the stub axle aka swing arm is bent. that's #2 in the diagram.

the hub could be tweaked, but that means the bearings would be wasted. so you'd probably hear and see that.

I'd pull the caliper and check the run out on disc, and pull the wheel and check the run out on the face of hub. if they both have run out then you know the problem is in the hub/bearings or the axle is off.

I'd totally trust a used hub. in fact, I'd probably source one and snap it on and then measure the run out. if it checks good, then you've solved the problem. if you still have run out, then it's time to replace the fork.

My money is on bent hub. Happened to me when I was sourcing used parts, these exact symptoms. Take a good look at the caliper as well, mine had a bent mounting bracket.

Thanks guys. Believe it or not, I haven't been able to test ride this yet, so no word on how it tracks. With the bent wheel, it wobbled like crazy at any speed over 15mph.

If that #2 spindle was bent, it seems like it wouldn't cause a wobble or runout. It'd cause the whole wheel to track straight, just at the wrong angle. So in other words the rotor would drag all the way around and the scooter may not wobble but it could try to turn depending on how exactly the spindle would be bent.

I already took it all apart and inspected the bearing, repacked it, put it all back together. Everything looked pretty good. My initial concern was maybe the bearing was knocked off center or just broken, but it wasn't. That's when I went with the next obvious thing, the wheel. Since the runout was not even across the whole wheel, but obviously out of true more in some spots than others, it at least needed a new wheel.

I think I'll probably try to find a used/good hub and swap it. I mean, if I'm going to take it all apart, I'll not want to put the potentially bent hub back on. It's not that expensive in the grand scheme of things, and I'm in no real hurry.

Thanks again, I'll post up as it develops.

So, these hubs are pretty hard to find used in the USA. Will a 2005 GT200 front hub work? Looks like ScooterWest thinks so, but just wanted to double check before I laid down the credit card.

Yes. Same part number from 2004 GT all the way up to 2014 GTS. ABS 2015 up is different part. AF1 parts catalogs for research.

https://www.af1racing.com/Vespa-Scooters-All-Models

Thanks for confirming that. I keep forgetting about AF1 Racing, even though they are right here in Austin and that's where I got the new lockset and ECU reprogrammed.

Fyi I got a used hub from a gt200 and it works perfectly. Thanks all.

That is good news having solved the issue. I also learned from that. Thanks for following through and sharing your results. It sucks when folks ask questions and then do not respond with the fix. Well done Sir!