Monza Jr - 16 wheels to 17 or 18?

[gregwils]

I got my '66 Monza Jr project home yesterday and started looking a little more thoroughly at it. The wheels are definitely toast, the front has a small hole rusted through. Fine, a perfect excuse for 17" or 18". Cars use the +1 where you maintain the same outside diameter by going to a shorter sidewall, but I don't think that's the case here. I guess I could go to a larger sprocket if necessary.

I am assuming that 17" would be the better choice so not to diminish the acceleration without swapping the sprocket. My bike's stock rims are 16 x 2.25 F and 16 x 1.85 R. There appears to be tons of fender clearance, especially for the 17's.

Can I find some used rims that have the same spoke count and pattern from an Asian bike of the same era? I see lots of them on fleabay. The hubs do seem to be different sizes which would get swapped with the stock ones, but I would assume impacts the spoke length? I saw DesmoDog's project where he did the same upgrade. I would prefer not to sink $400 - $500 in a new set if I can avoid it.

Sorry for the novice question. I know next to nothing about what I am doing. I posted this on BevelHeaven too, but doesn't seem to be much action in the single's forum, forgive the repeat. Thanks.

[DesmoDog]

I've forgotten the details now but I think the 160 swingarm is a touch shorter than a 250 swingarm? From what I remember, if you're not running a rear fender an 18" wheel/tire just barely fits. With a (stock) fender it won't work.

The rims I used were NOS Benelli parts so they didn't cost all that much. Cosmo isn't around anymore though so I have no idea where you could find them.

You will have to get new spokes for them but that isn't an issue. (It's also not cheap though.) Buchanan's will figure out what length you need if you send them the dimensions of the hubs and rims.

FWIW I've pretty much given up on mixing and matching wheel parts due to the angle of the spoke holes. I've been burned one to many times and now just order new alloy rims from Buchanan's, drilled for the hubs I want to use. It's not cheap but it saves a lot of screwing around. I don't know if steel rims are more forgiving on spoke hole angles, I'm assuming they are.

[gregwils]

Thanks Craig. Funny I just got done reading a post of your's on another forum where someone else was asking a similar question and you had the exact same response.

You know what, I get it. Every time I try to cut corners, I end up saving about $1 for an inferior result and I want to kick myself for trying to be cheap. I will probably call Buchanan's and order a set of Excel's. I am going to try for 17's. There appears to be adequate clearance to gain a 1/2" under the fenders. Let me know if you think I am crazy.

[DesmoDog]

Originally Posted by gregwils

Thanks Craig. Funny I just got done reading a post of your's on another forum where someone else was asking a similar question and you had the exact same response.

I'm glad the response was the same, I seem to be forgetting a lot about this stuff lately!

I think 17s will work fine. It's coming back to me now.. the larger bikes have a little kick-up in rear hoop, on the 160 it's flat. IIRC that's where the issue with fitting a fender and 18" wheels comes from.

I need to order some Excels for my 350. The generic alloys I bought, that I was assured would work, don't. Spoke holes are wrong. Grrrr....