Author Topic: Front wheel offset  (Read 1722 times)

Offline PHILIP2908

  • SOHC Associate
  • Posts: 95
    • View Profile
Front wheel offset
« on: November 09, 2019, 08:21:45 PM »
Hello All,
I've been a member for a few years now and always wondered why I'm still a 'newbie'.... I've figured out its the number of posts and need to get to 50 for the next level. So here's another! Bit of background:
I bought the DK special about 4 years ago and had various problems; leaking head gasket, had to take the engine out, stripped threads in a cylinder head (which was seemingly made out of Lurpak) and dozens of other things. Plus getting worked to death in my sales job ('if you don't sell enough then you get the chop'), decorating demands from the chief fairy, 2 teenage daughters ("you're not going out like that") and a multitude of other things that have got in the way of getting my 750 back on the road.
Next summer is the target and one of the things I have to do over the winter is swop the Lester magnesium wheels for spoked items. (the Lesters will be for sale soon)
To this end I bought a couple of spoked wheels off ebay just so I could get the hubs (the Lesters have the hubs cast into the wheel). I've started with the front and after reading the CB750 book by Mark Paris, I noted the fact that the front wheel is offset, from new, 3mm towards the left (as you are sitting on the bike). This was done so the racing fraternity could fit another disc on the right without too much modification. But this means that the front and rear tyres follow different paths and give rise to head wobble; something I remember from my old K2 which I restored in 1992.
The question is: as I am about to build the front wheel with a new rim and spokes, should I move the rim over to the right by 1,5mm so the wheels follow the same path?
I don't know if it's clear enough in the photo but the measurement on the speedo drive side to the fork leg is 33mm and on the disc side to the fork leg is 30mm. A move of 1.5mm towards the disc would correct this. Apparently dealers complained back in the day as when the 750s were on display in the showrooms they had to bend the front mudguard to make the wheel appear central other wise they looked a little odd. Have you looked at yours?
Apologies if this has been covered before, but a search of the site using 'wheels' results in 000's of posts which I don't have time to read.
In the photo, check how roached out the rim I bough
[ Guests cannot view attachments ]
t is. And the crappy Dave Silver fork gaiters that disintegrated after 12 months - one of the worst £18 I've ever spent.
Any advice welcome.
Thanks in advance.
Phil in Cheltenham.
1974 Honda XL250 K0 - Silver - owned for 32 years. Not running at the moment
1972 Honda CB750 K2 - Now candy apple red - Ex USA, a DK special - needs a lot more work than I thought - very quickly becoming a DS special...

Offline Bryanj

  • Grogu
  • *
  • Posts: 10692
    • View Profile
Re: Front wheel offset
« Reply #1 on: November 09, 2019, 08:59:30 PM »
I always thought the rims were central to the hub and i will only use genuine Honda gaiters as most pattern ones are crap

Offline Erny

  • CB750K7 CB550K1
  • SOHC Pro
  • Posts: 522
    • View Profile
Re: Front wheel offset
« Reply #2 on: November 09, 2019, 09:00:58 PM »
Hi Philip,

yes, move your rim 1.5mm to make it in center between forks, I did also on my CB750.
I followed Mark's book too.

BTW, these Lester's depending price and conditons, I would be interested ;)

And use genuine Honda gaithers if still possible to obtain
CB750K7 US model (1977)
CB550K1 US model (1975)

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: Front wheel offset
« Reply #3 on: November 09, 2019, 09:07:12 PM »
No oftet on any standard Honda CB SOHC/ 4 wheels.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Trigger

  • Grogu
  • *
  • Posts: 8434
  • Engines built on reputation, not advertising.
    • View Profile
Re: Front wheel offset
« Reply #4 on: November 10, 2019, 08:23:02 AM »
You old boys worry toooo much. The mudguard is off set in the front as, the brake arm is in the way. I have never come across a wheel on a sohc off set, you true it central  ;)

If you off set the rim to the hub, it would look pissed compared to the mudguard
« Last Edit: November 10, 2019, 08:29:59 AM by Trigger »

Offline Seamus

  • SOHC Pro
  • Posts: 745
    • View Profile
Re: Front wheel offset
« Reply #5 on: November 10, 2019, 08:31:47 AM »
Build them centrally, lots easier than adding an offset.

Offline JamesH

  • SOHC Jedi
  • Posts: 2846
    • View Profile
Re: Front wheel offset
« Reply #6 on: November 10, 2019, 09:00:24 AM »
Every rim I’ve taken and measured from an original SOHC bike has been centred in the hub (both front and back). I always center the rim to the hub when rebuilding.

Offline steff750

  • SOHC Expert
  • Posts: 462
  • THE POWER OF DREAMS
    • View Profile
Re: Front wheel offset
« Reply #7 on: November 10, 2019, 09:32:50 AM »
 ;) it is only the hub is offset and not the wheel the spokes are the same length and will keep the hub central to the rim its not rocket science i have laced quite a few wheels without any problems books can be wrong or even misunderstood ::)

Offline JamesH

  • SOHC Jedi
  • Posts: 2846
    • View Profile
Re: Front wheel offset
« Reply #8 on: November 10, 2019, 09:43:35 AM »
;) it is only the hub is offset and not the wheel the spokes are the same length and will keep the hub central to the rim its not rocket science i have laced quite a few wheels without any problems books can be wrong or even misunderstood ::)
I’m talking about lateral offset obviously lol

Offline steff750

  • SOHC Expert
  • Posts: 462
  • THE POWER OF DREAMS
    • View Profile
Re: Front wheel offset
« Reply #9 on: November 10, 2019, 10:59:47 AM »
Quote
I’m talking about lateral offset obviously lol

obviously


james i have sent you a PM

Offline Bryanj

  • Grogu
  • *
  • Posts: 10692
    • View Profile
Re: Front wheel offset
« Reply #10 on: November 10, 2019, 11:30:39 AM »
I read that the very early hubs where dimensional different in width, enought to make it difficult to twin disc. 3mm is in my mind and it may well be that size that was in Marks book, as i dont have a copy and havent read it i cant comment further

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal