Tyre Sizing

[xbally]

You were lucky to find a set of cush drive rubbers if yours is an "A" like mine. I bought a pattern set but they didn't fit. I think they were off something like a CG125 IIRC. My RS has been the bike I run all year round although I probably don't do more than a 1000 miles a year on it since retiring. I only go out on clean dry roads though whatever the time of year. If it's cold I have a heated vest I can use on the RS although it doesn't seem to work on my other bikes. There must be some sort of problem with the wiring connectors which are different on the other bikes. The winter is not the best time to be working on the bikes either unless you have mild weather or a good heater.I've just bought one of these :



https://www.screwfix.com/p/erbauer-freestanding-or-portable-ptc-workshop-heater-2500w/639FV?gclsrc=aw.ds&gad_source=1&gclid=Cj0KCQiA_9u5BhCUARIsABbMSPuhmqBk8Zw7x7rosl0bvMeEW7OT86apRLa0bymi8IKRX7JTejGARscaAggaEALw_wcB

[xbally]

Rear wheel is now back in and everything has been tightened up and ready to go when / if we get any decent weather at this time of the year.
There was a bit of a dilemma with which way the spindle should be fitted. The owners' manual appears to show it from the opposite direction in the Haynes. I put it back in the same way as it came out as I knew that worked. Just got to bed in the new tyres now and hopefully it will have been a worthwhile exercise.

[kevberlin]

Hi Martin.
I had the same issue regarding the rear spindle.
The various diagrams and pics I saw indicated to me that the rear axle nut (with split pin) should be at the same side as the sprocket.
Mine was previously fitted the other way around. I reversed it to comply with the manual and the cmsnl drawings.

Kev

[iansoady]

I don't think it matters which way round the spindle is. I generally fit from the left (using a smaller diameter bar first to line stuff up) as I find it easier that way. I can't see any engineering reason for one way or t'other.

[xbally]

I think you must both re right Kev and Ian.
Mine's fitted like yours Kev with the axle nut on the same side as the sprocket.
I usually line everything up with a block or blocks of timber under the rear wheel which saves having to ask the wife to knock in the spindle while I hold everything in place.
I once had a KH 400 triple which kept pulling the rear wheel out of alignment .After some head scratching I either realised or was told (can't now remember which) that I'd either completely omitted or fitted  a spacer in the wrong place or the wrong way round.

[xbally]

I finally got to do a brief road test yesterday on the new tyres.
Not ideal conditions for bedding them in with a mix of gritting residue and damp patches but mostly dry.
I don't know what it's like in other parts of the country but round here there are gaping pot holes EVERYWHERE and temporary traffic lights seem to proliferate on an increasing basis.
Anyway I thought I detected an imbalance in the wheels but wasn't sure whether it was the front or back -or both?
Both tyres appear to have been inflated to around 40 PSI. Being a lightweight the RS is said by Mr. Haynes to require respective pressures of 24 front 32 rear for solo use.
Although I couldn't see too well in the fading light the front appeared to be correctly aligned on the rim but I wasn't so sure about the rear. The tyre soap which remained didn't help as it obscured the markings on the tyres used to check the alignment so I cleaned the sidewalls of this too.
I inflated the rear to 60 PSI in attempt to centralise it, then reduced the respective pressures to the correct specs and went for a brief further test ride where things seemed to have improved somewhat.

[iansoady]

Like you I'd be looking at something like 26/32 front and rear. It's surprising that the fitter didn't ask what you wanted. I've got the back wheel out of the little Yam and will probably be taking it and the tyre for fitting today.

[xbally]

Like you I'd be looking at something like 26/32 front and rear. It's surprising that the fitter didn't ask what you wanted. I've got the back wheel out of the little Yam and will probably be taking it and the tyre for fitting today.

Good luck 

[themoudie]

Morning to you both,

2.75 x 18 front on the Duke 450, 26psi and 90/90 x 18 rear, 32psi. Crossply

2.75 x 18 front on Morini 125H, 26psi and 3.00 x 18 rear, 32psi. Crossply

110 x 17 front SRX600 monoshock, 28psi and 140 x17 rear, 32psi. Crossply

110 x 17 front SRX600 monoshock, 30psi and 140 x17 rear, 34psi. Radial Michelin.

100 x18 front SRX600 twinshock, 28psi and 120 x 17 rear, 32psi. Crossply.

I was advised when fitting the the radials to the monoshock to use 32psi front and 36psi rear, the same as for the SZR660. It felt lethal! Dropped by 2psi front and rear and feels much better. I have run at the crossply pressures, 28psi and 32psi, but feels a bit squirmy.

As for not seating the bead correctly and just leaving the pressure at 40+psi! That tyre fitter would loose my custom instantly. I always check that the bead is seated and the tyre is at the correct pressure, with the valve mark on the sidewall aligned with the valve, if the manufacturer has marked the sidewall. It indicates the lightest side of the tyre and makes a difference when balancing the wheel. I only bother having the front wheel balanced, as that is the most sensitive to imbalance at the speeds I am using on the road.

Good health, Bill

[xbally]

Morning to you both,

2.75 x 18 front on the Duke 450, 26psi and 90/90 x 18 rear, 32psi. Crossply

2.75 x 18 front on Morini 125H, 26psi and 3.00 x 18 rear, 32psi. Crossply

110 x 17 front SRX600 monoshock, 28psi and 140 x17 rear, 32psi. Crossply

110 x 17 front SRX600 monoshock, 30psi and 140 x17 rear, 34psi. Radial Michelin.

100 x18 front SRX600 twinshock, 28psi and 120 x 17 rear, 32psi. Crossply.

I was advised when fitting the the radials to the monoshock to use 32psi front and 36psi rear, the same as for the SZR660. It felt lethal! Dropped by 2psi front and rear and feels much better. I have run at the crossply pressures, 28psi and 32psi, but feels a bit squirmy.

As for not seating the bead correctly and just leaving the pressure at 40+psi! That tyre fitter would loose my custom instantly. I always check that the bead is seated and the tyre is at the correct pressure, with the valve mark on the sidewall aligned with the valve, if the manufacturer has marked the sidewall. It indicates the lightest side of the tyre and makes a difference when balancing the wheel. I only bother having the front wheel balanced, as that is the most sensitive to imbalance at the speeds I am using on the road.

Good health, Bill

As always Bill, very good and practical advice-thank you.
I looked for the tyres you recommended previously but couldn't find any in the sizes for the RS unfortunately.
Yes the fact that the pressures were wrong and possibly the rear wasn't seated correctly does make me wonder where I should go next time. Ian's chappie isn't too far away from me. I'm hoping not to have to fit any more tyres for the forseeable future!
With the GPZ500 I wasn't asked what type of tyre was on the back as I believe if mixing you should only have a crossply front mixed with a rear radial.

[iansoady]

I've just picked up my newly fitted tyre from Lee at Stealth. An excellent job for £20. He did say he's never agree to fit another Chinese tyre as it had been a real struggle even with 2 of them!

In nearly 60 years of riding this is the first bike tyre I've had fitted by anyone else but am pleased with the outcome.

[xbally]

Update to this thread....
Not on my Thumper but since fitting the new Mitas front to my GPZ500 the old worn rear (a Conti dated 2013) has developed a slow puncture. I think it's a rim sealing issue.
Anyway I decided it would be the safest option to replace the Conti with the same rear Mitas. The Conti has no age related issues I can see but the centre tread is worn but well within the legal limit but not worth the bother of fixing the leak IMHO.
Can I get a Mitas replacement  anywhere? No chance-not at least until Mid February by all accounts according to the MOT tyre place who did the earlier work on this bike and my RS250. No amount of internet searching could locate one.
I decided on a (quite a bit more expensive) Pirelli from my local bike shop and asked them to order one yesterday. They then phoned me back to say they couldn't get the Pirelli (Angel) only a Diablo which is more expensive as it's a sports type compound instead of the sports tourer I was after. Alternately they could only offer a Michelin which was £3 less than the Pirelli.
I'm still waiting to hear back from my usual MOT tyre place with an alternative fitment-but have phoned them 3 times so far so I shan't be bothering again.
I've decided to keep pumping up the rear Conti for the time being....

[iansoady]

I found the same dearh of Mitas when I was looking earlier in the year (as a side issue there seem to be no NGK plug caps available either!) The kind folk at Central Wheel did say they could probably source me one but that was a couple of months ago.

I blame brexit myself. Or maybe a trump effect?

[xbally]

Yes Ian. I requested a notification from Central Wheel or their tyre offshoot when stock comes in.As you say this seems to be happening more often recently and could be due to many factors including the ones you mention.