swap 19" front rim for an 18" front rim

[Guest]

Hi Guys, I have a gs750 1979 with spoke wheels and dual disc which needs rebuilding and would like to know the pro's and con's of swapping the 19" front rim with an 18" front rim any advice would be great thank you.

[John Park]

Which 18" rim; what tire do you plan to run on it? What do you not like about the 19" rim? If you plan to use an 18" used rear rim, the spoke holes will be at rather different angles compared to those for a front spool hub.

Lots to know, preferably in advance.

[roberthiggs@hotmail.com]

Hi John, I was thinking of replacing the steel front rim with an aluminium 18" front rim to reduce weight and improve steering and there is a good range of 18" front tyres to choose from. If it is a viable option then i was going to speak to the wheel rebuilder as to what brand would be best and tyre size and i have no dislike for the 19" front rim i am just looking at other options and asking for other people's advice as i value other people's input .

[John Park]

I'd think that a 2.50 18 Borrani would be my choice; you could run a 100/90 or 110/90 18 on it as long as you had fender clearance. The 100 would be an inch shorter and quicker turning and the 110/90 is about the same diameter as the original 3.25 19 [??] .

I don't see much point in going narrower than a 2.50 rim. Or wider.

Do you have a tire in mind?

[postman_pat]

I have used an 18x2.15 Excel Takasago rim with a 100/90x18 on standard GS750 forks to good effect. This set-up drops the front end by approximately 1/2", but because the standard GS750 has relatively long forks and very conservative steering geometry, you are unlikely to notice any adverse handling effects - I didn't anyway. I also fitted the front fender from a 1983 GS750 as it matches the curvature of the wheel and tyre better - not only a cosmetic improvement (in my opinion), it also weighs considerably less than the original steel fender. I also fitted a Tarozzi fork brace - just to stiffen things up a bit.

At the rear I fitted an Excel rim (18x3.50), wearing a 140/70x18 tyre. This dropped the rear end by approximately 3/8"-1/2" from the original 120/90x18. I thought that overall this dropped the bike a little too much, front and rear - so I compensated for that by fitting a set of Ikon 7610-1296 shock absorbers, which are standard replacement for Honda CB750Ks. They are 339mm in length, compared to the standard Suzuki length of 325mm.

I had the front and rear rim custom drilled to suit the hub then laced and trued the wheels myself. For the front wheel you can use an OEM Suzuki spoke set (Part no.55320-18420). At the rear I used the original GS750 spokes which I cleaned and zinc-plated myself.