Topic: Modern low profile tyre look on rear of 400f

[neevo]

Doing a cafe job on my 76 CB400f, it will be racer style with modern touches. The rims and spokes were destroyed prior to buying it and hence I have the option of upgrading the widths.

Currently looking at buying Sun Rims and SS spokes from Buchanan's. Their selection is good in the Suns and I need them anodized black too. I know there are performance benefits in the following setup:

Front: WM2 / 90x90x18 tyre
Rear: WM3 / 120x80x18 tyre

I like the look of modern sports bikes rear tyres and would like to emulate this in a safe manner that doesn't compromise handling too much and fits in the swimgarm without fouling.

Also keen to make sure that the width I choose has options for tyres rather than some exotic size that is impossible to cater for.

Can anyone help?

[camelman]

You are limited on tire width due to the location of the output sprocket on the engine. I'm sure you could get some modern rubber on there that would fit if you laced up 17" rims, but you are going to spend a fortune on rims and spokes. I'm building a 350f racer right now that is getting racing boy rims on stock hubs with stock spokes. Total cost is $350 or so for the wheels (building them myself) and $250 or so for tires, tubes and mounting. I'll run bridgestones on the street and maybe an Avon race tire if I ever make it to the track.

Regarding tire widths for best handling, keep the front and rear close. I have a 90/90 up front with a 110/90 in the rear on my 350f (badically the same dimensions as your bike) and will be either increasing the front to a 100 or decreasing the rear to a 100. It seems that the 20mm difference is a bit too much.

Camelman

[neevo]

So anything wider than a WM3 (2.15) is not going to fit?

In that case:

1. Can i safetly fit a 130 to a WM3?
2. Can you get lower profile rear tyre than an 80?

[crazypj]

Go 90/90 110/90.
 They look OK on 'correct' rims and with decent shocks, forks, ets wil lgo round corners faster than you thought possible without any drama (I did several 400f's in the 80's)

[neevo]

Thanks PJ, fighting the reality of your advice I suppose as I would like something tough looking and that really gets into the 120/130 70 range.

Think it's a loosing battle.

Very much appreciate all your help PJ, here and over on DTT, just thought someone here might have gone bigger. I suppose there is a reason no one has done it.

[crazypj]

I also watched my brother sliding down the motorway at 90+ when his 400 decided it didn't like him.
 Larger tyres make it real unstable if you get hit by a crosswind (but nowhere near as bad as CBX550)
 He also managed to wreck coming out of a tunnel at 90+, side wind again (with STOCK tyre sizes)
 It's why he got his nickname about 33~34 yrs ago, 'Wobble'
He's on left in pic (around 1980)

 Sorry, twas 1982, found this one

[neevo]

Got some hair happening there PJ!

Got any pics of the 110 mounted up?

[crazypj]

I got a bit fatter in the last 29yrs 
 I think I only have pics of 110 on WM3 'loose' (not fitted to bike)
I may have a pic of Brendon's 360 with WM3 and 110, I'll check
In the meantime


 90/90 front, 110/90 rear, both on WM3

 Theyare flanged rims, black non flanged make tyres look bigger.
 I used XS650 alloy rims F&R for my bikes, XS650 steel rim on Brendon's.
He painted his satin black.
 Use 400 rear rim on front and get XS rear rim for rear (should be able to get a used rim pretty cheap, XS650's are real popular in Oz)

[neevo]

Ah yeah, that 110 looks fine. Cheers PJ.

Buying new from Buchanans for a couple of kidneys, hence I have the options to do what I like.

[crazypj]

Oh yeah, I forgot