Moulton TSR 9 - BB size ?

[jerrysimon]

Recently converted by TSR 27 to a TSR 9 (rebuilt a wheel and used the SRAM 9 speed cassette that came with the SRAM dual drive). It had a 44T Sturmey Archer crank fitted but needed to upgrade to stock Sturmey Archer 55T crankset that is fitted to TSR 9s. At the moment the BB is a 68 x 111mm made by Sunrace which I think is the one that comes fitted stock by Pashley to a TSR 27.

However the new crankset has two guards and the inner one just touches the frame (see pic). I think a 68 x 113mm will do the job and hopefully the chain line will be ok.

I guess I shoulld measure the chain line, but would be interested to know if anyone knew what size Pashely fit as stock with this crankset

I posted this on the moulton web site but hoping I will get a faster answer on here as I know there are a few enthuiasts here

[jerrysimon]

Ok measured chain line to the middle (5th) sprocket and its 44mm. Going from a 111mm to a 113 mm will take me out another 1mm which would be sufficient to clear the frame with the dual chain guard and set the main crank chain line at 45mm, so looks good to me

I have 68 x 113 BB in another bike so will whip that off qucikly to check before I purchase another

[Brucey]

good idea to check this as you intend; not all bottom bracket spindles are lengthened equally both sides when you go up a size.

FWIW if it doesn't work out you can usually add a thin spacer behind the RH cup.

cheers

[jerrysimon]

Many thanks Brucey I just read about the thin spacer on the RH cup on the famous, late great Sheldons site

It was a good job I removed the Sunrace BB. The bottom bracket frame housing was full of swarf where they had tapped the thread out, Looks like a real late Friday afternoon job. I did check the thread and thankfully it wasn't damaged

Now fully regreased and BB goes in by hand, until I can then tighten it.

[jerrysimon]

Spent the day faffing around with the 113 BB from another bike and then trying to use shims on the stock 111mm BB to space it out.

For I moment I thought I had it cracked, by moving the chainring to the outer position (a tip from Sheldon's site) but I had to reverse it to do that and there is a ridge which I assume stops the chain coming off when you go down to the lowest gear, as that is what then happened

Shame as the fit was then perfect fit with the stock BB and no shims, leaving just a few mm clearance from the frame.

I then tried the 113 BB from another bike which seemed to work fine, though more space than needed really, as shown below. It was a UN55 113 BB but I could not then get the left cup to go in and did not want to risk the threads.

Clearance with Shimano UN55 133mm BB

In the end I used the stock Sunrace BB with a 1.5 and 1mm (total 2.5mm) shim which left enough room i.e about a business card width at the closest point (the guard does not seem to run even all round). Chain line is around 45.5mm which is close enough. I assume there are enough thread left on the BB right hand as shown ?

Tiny clearance with stock 111mm Sunrace BB with 2.5mm of shims

Shims on stock 111mm

Took it for a ride and smooth changes up and down the gears so at least it gets me on the road. I may now purchase one of the stock Sunrace BBs but with a 133mm spindle length.

A couple more pics attached for interest, showing bike in its naked form (11.5KG) and with a front carrier, bag and KlickFix fitting mod.

Bare Bike

Bike with klickfix fitting and bag

All in all a great day fettling, whilst we are on Coronavirus lockdown (except one bike ride a day) here in the UK

[jerrysimon]

Close up of KlickFix mod

KlickFix fitting attached to Front Carrier

[Mick F]

Can't help in the slightest regarding a BB for a Moulton TSR.

My BB and chainset is a Stronglight thingy.
http://www.stronglight.com/stronglight/ ... uit?id=276
I fitted a 61t outer ........................ but came originally at 58/48/34

[philvantwo]

Not a helpful post at all there from mick f.

[Mick F]

Yes, it was helpful, but in a negative way.
Insomuch as my TSR didn't come with anything like that chainset.

Nearly everyone on here knows I have a Moulton, so if I'd not answered, people might think I'm ignoring the thread.

[philvantwo]

Another Moulton with too many spacers underneath the stem! Why don't they just make the frames bigger?

[Brucey]

Another Moulton with too many spacers underneath the stem! Why don't they just make the frames bigger?

because it is a 'one size' frameset, and small people ride moultons too, often using dropped bars.

cheers

[jerrysimon]

Another Moulton with too many spacers underneath the stem! Why don't they just make the frames bigger?

Actually it's unique to me, in that I like a very upright ride being in my late fifties and having back problems

You should see my Raleigh Moulton MK3

Alongside my belt driven TSR 2, long since gone.

[philvantwo]

Well the red bike looks slightly better, but these Moulton bikes just look a bit 'heath robinson' to me, as if things have been added on as an after thought. What actually inspires people to even buy one?

[Brucey]

Marmite alert!



cheers

[Mick F]

Well the red bike looks slightly better, but these Moulton bikes just look a bit 'heath robinson' to me, as if things have been added on as an after thought. What actually inspires people to even buy one?

For me, I wanted a change to something "different" and "quirky".

What I got was a can of worms.

The gearing was pitifully wrong, the brakes were rubbish, and I hated the Tiagra STIs ............. to name a few bits ................so I set about improving it all.
Lots of foibles but I've surmounted all of them.

The rest is history, but what I've ended up with is fun to ride and I enjoy it ......................... and so would you.