Topic: 18 inch front and back wheels cb750

[pn2501]

Hi i'm not sure i'm posting in the right place  (if i'm not please delete this post)

I've read the FAQ on wheels (also did a search and i couldn't find a post relating to my question)

A little bit of background, I bought a non roller cb750k2 basically really just frame and engine (some other odds and sods), i'm about to pull the trigger on a set of adjustable triple clamps for GSXR forks from Cognitomoto, as i'd like to keep the bike to as stock geometry as i can (also not a fan of the 17inch wheels), and if possible somehow improve the handling over stock, and i'd like to run 18inch front and back rims (if this is a bad idea let me know)

I'm after the optimal rim and tyre sizes from your guys experience please also feel free to suggest tyre's that would be best for my application.

Also sorry in advance you guys probably get this question in one form or another way too often... sorry!

[calj737]

You might actually ping Devin with this question since he runs 18/18 on his 750s with the GSXR front end. He's done the geometry calculations over and over on those bikes and his 550.

[pn2501]

Thanks for the reply Cal, Much appreciated.

Maybe I need to pose my question in a different way (probably not making any sense haha), I've read through a few of Devin's threads regarding his conversions (particularly the conversations between himself and Retro Rocket) I know on all his personal bikes he runs the non adjustable front ends with 17" wheels with modern sport bike Tyres and a 550 swing arm on his 750.

Plugged in geometry calculations are cool but I'm after real world feedback, given that the adjustable front end is the same geometry as standard (or so I'm lead to believe), and I read else where people run 18's front and back (assuming someone on here might have As well ), and standard is 18" rear and 19" front if I were to run 18" on the front what would the handling characteristics be (would it make handling worse? What I've read the 19" makes the bike more stable)

I'm also planning on running custom rim widths based on standard geometry and 18" font and back (if it's no worse than running a 19" up front) what are the optimal tyre and rim sizes?

[calj737]

I was just with Devin Tuesday night. He's got 18/18 on his new 750. We discussed specifically his adjustable triples and this point in fact as it pertains to his 550, my 500 (in build) and his new 750.

FunJimmy's Interceptor might be another source, though I'm not sure of his sizes.

[pn2501]

Thanks again Cal,

Gathering the updates on instagram he's a bout half way on that 750.

Looks like i might shoot him an email then.

ill check out FunJimmy's Interceptor aswell

Cheers for your help.

[pn2501]

ok so found a thread with a bit better searching with the right keywords clearly didn't try hard enough first time around.

http://forums.sohc4.net/index.php?topic=56494.0

after reading that and this Thread

http://forums.sohc4.net/index.php?topic=144395.0

I've Decided to go with

on the front Avon AM26 110/80v18 on EXCEL WM4 (2.50) x 18" NON-DIMPLED ALUMINUM RIM

and on the rear Avon AM26 130/70-18 AM26 on EXCEL WM6 (3.50) x 18" NON-DIMPLED ALUMINUM RIM

any potential problems anyone can see with that specifically about the non-dimpled aspect?

[Retro Rocket]

any potential problems anyone can see with that specifically about the non-dimpled aspect?

No...

[pn2501]

Cheers Retro,

expect a few more stupid questions from me in the future, about to do a search on dyna 2000's and wether they are ideal for Australian Conditions

[Retro Rocket]

Cheers Retro,

expect a few more stupid questions from me in the future, about to do a search on dyna 2000's and wether they are ideal for Australian Conditions

Dave500 has non dimpled sun rims on his 500, they look great and work fine, i'm sure he's not the only one......

[FunJimmy]

18" wheels ALL around are considered best for performance on these old gals. In actual fact, all you're talking about is matching the front to the rear. Triumph Thruxton,s use 18" wheels too. I went with 2.5"x 18" front and 3"x 18" on the rear. You might be able to go a bit wider but consult the tire manufactures recommended rim width first. I was also running Bridgestone BT45 (same as Thruxton) tires but have since switched to Avon AM26 Roadriders

[pn2501]

@Retro

Just checking Dave's bike out yeah looks decent got me more sold, i'm thinking of getting them either anodised black or powdercoated, i'd assume anodising would be the better option? and probably more costly.


@funJimmy

The max size is 4" for the rear with that sizing in the am26, Excel don't make a non dimpled 3inch rim,

i also contemplated going 150width tyre on the rear but it would a:) probably look silly b:) struggle with fitment, c:) not perform optimally.

on silly idea's i had another one that probably wouldn't work, and that was attempt to run the gs spoked tubeless rims



just to be different but i dismissed it as silly and too much work. 

[calj737]

Buchanan sells their Sun in non-dimpled at 4.25". Easily fits a 150 tire if you choose that size. Even offered in anodised finish-

[pn2501]

Cheers Cal, Yeah they're probably cheaper as well. are those what Devin is going to run on the new 750?

Stupid question time, would the 150 adversely affect the handling in comparison to the 130? 

[FunJimmy]

Cheers Cal, Yeah they're probably cheaper as well. are those what Devin is going to run on the new 750?

Stupid question time, would the 150 adversely affect the handling in comparison to the 130?

Not adversely but turn in and cornering will be a bit slower than with a 130.
I think chain line and swingarm clearance would be a concern.

BTW, I had both of my rims anodized for a dozen Miller Highlife and everything else on the Interceptor was anodized for beer too. Go chat with the guy in the shop of the local anodizers and tell him you're just tinkering around on a vintage Honda. Ask if they can toss your stuff in with a commercial run for some beer or herb. You'd be surprised how accomodating they can be if you're doing this for recreation and not a commercial enterprise.

[pn2501]

Thanks FJ,

I'm thinking of running the Dresda replica swing arm (carpys) on the rear, mainly because i don't have a swing arm at all at the moment, i know from your thread you run one ( a real one), the dimensions are basically the same as a stock 550 swing arm is that correct? and on a 750 would extend the wheelbase?

apparently this can alleviate the chain line and swing arm clearance.

http://cognitomoto.com/products/3-8-9-5mm-rear-offset-sprocket-spacer-for-cb750?variant=616303501

but wouldn't fix the turn in and cornering issues, plus it's an extra cost.

if i go with the excel rim it will accept the 130 or the 150 if i go with the sun rim i'm stuck at 150.

the excel rims are winning at the moment, i assume in terms of quality both are on par? (think i read somewhere once that excels were pretty good)

also worth noting is that anodising the sun rims from buchanan's cost $48 per wheel. and it will still have the branding all over them (something i don't like about the sun rims aesthetics)

there is a local guy not far from my work i might try your approach FJ, hopefully i do alright at profiling him to ascertain what vice to bribe him with 

[calj737]

The rims that Devin sells are Excel knock-offs and can be had in anodised finishes. Didn't notice whether they're dimpled or not. But there's no branding on them.

From all I've read, the 18x130 seems to be the preferred rear tire for overall handling. The 150 I'd suspect does exactly as FJ and others mention. The 140 is an option and should also fit/clear if you prefer.

Buchanan last I looked, was no longer offering their Sun rim in a gold finish, but I know the Excels can be had in it, Devins too. I may pop by his place later this AM and see if he's about, and snap a picture of his rim for your eyes.

And an offset sprocket front and rear is certainly an option for tire/chain clearance.

I've ot Kevin's (TTR400) boxed swift arm on the back of my 550 and am running a 130 tire. I've got heaps of room for more meat with it. It's factory dimensions for a 550, but the flat tubing does seem to create a tad more wall-wall clearance than the round/oval legs provide.

[pn2501]

Again Cheers Cal,

Yeah the non branded knock offs are dimpled but again cheaper.

Also thanks for putting me onto ttr400.com thats another parts supplier to add to my list, didn't know he existed (needs some better SEO methinks) 

If you don't mind me asking how much did the dresda swing arm set you back? it looks like a much better quality item than the carpy's one, also that cbr1000 rear hub assembly has caught my eye.

[calj737]

If I recall, it was about $500USD, but shipping from South Africa to the US was expensive. I now understand how you blokes down below suffer...

Kevin's goods are very well made. CroMo square tubing, and milled axle stays. It's not a true Dresda, but it certainly performs like one. And Kevin is about the nicest, most honorable guy I've ever dealt with.

Background: when I first ordered the swing arm, SA was dealing with a Postal Workers Union strike. Nothing going out, nothing coming in. Went on for weeks. Ultimately, he was able to ship it via their postal service to save the expense of Express carrier. Unfortunately, the first unit never arrived. Nor did it get returned to him. After 10-12 weeks of waiting, he sent another. I offered to share in the expense, but he refused.

He's a small shop and to have done that at the word of a complete stranger is pretty high water in my book. Guess I have an honest face via email... No disappointments whatsoever with the product or man behind the brand.

Another option for you to consider is the new CalFab arms from MotoGP Werks. Check them out via their facebook page. Retro also has a thread somewhere along in here with pictures and links. They're the shop that makes the highly coveted Yoshi 4:1 replica exhausts.

[pn2501]

SA is closer geographically to me, but the shipping would be even more expensive coming out of there.

I've spent some time in Africa, i wouldn't trust their postal service (it's probably still on route to you) He certainly does sound like he deserves the business, lots of shonk's out there, so the good guy's deserve the work.

Found retro's thread

http://forums.sohc4.net/index.php?topic=139903.25

wow they do look special, like always way too many options haha.

Yeah i saw those Yoshi's on Tweakin's F2 project page, seriously considering them, although thinking of something custom made here possibly, outta some cone engineering stuff.