Chain wear checker for a Brommie.

[Banjo]

Does anyone know what type chain checker I should use on a Brompton ML6. ?

Also any special maintenance I should do.I am giving mine a pre winter clean lube and look over.

 

[fossyant]

A chain is a chain - Park Tool checker (not expensive)

 

[Banjo]

Thanks for Ithe reply.I don't know why I thought Brompton chains would be different.

I already have a park tool checker it's telling me it's between .5 and .75 worn so it's a new chain time.

hopefully get away with the sprockets if new chain slips will change them then.

 

[mitchibob]

Thanks for Ithe reply.I don't know why I thought Brompton chains would be different.

I already have a park tool checker it's telling me it's between .5 and .75 worn so it's a new chain time.

hopefully get away with the sprockets if new chain slips will change them then.

Change the sprockets too. They'll need it, believe me.

 

[Yellow Saddle]

Change the sprockets too. They'll need it, believe me.

Why?

 

[Kell]

They do seem to be quite sensitive.

I also change my chainring at the same time every time, but this might actually be overkill.

 

[Fab Foodie]

Why?

I think they do a lot of work only being 2 small diameter rings and being close to the ground they pick-up a lot of shoot. They’re not expensive and easy enough to change

 

[Yellow Saddle]

I think they do a lot of work only being 2 small diameter rings and being close to the ground they pick-up a lot of shoot. They’re not expensive and easy enough to change

Even so, you can still get about three chains from a cassette before it needs replacement. I don't see the point in routinely replacing something.

 

[Kell]

Even so, you can still get about three chains from a cassette before it needs replacement. I don't see the point in routinely replacing something.

I've always been told that (and I know you're the chain guru) but I think that would mean changing your chain every couple of months. I change my whole drivetrain out twice a year as I once snapped a chain, it dumped me on the cross bar and I broke my coccyx - meaning I was off the bike for about 3 months and still have problems today. Can't sit in a car for any more than two hours without having to pull over and stretch my legs and relieve the pressure.

The first time I tried changing my Brompton chain was at 6 months. I put the new one onto the old cogs and it just jumped about the entire ride. New cogs (and chainring) and it was fine.

For the sake of £50 twice a year I think it's worth it - especially as one day off the bike costs me £9.40 in parking, then Boris Bike hire, Tube fare or bus fare.

 

[chriscross1966]

Even so, you can still get about three chains from a cassette before it needs replacement. I don't see the point in routinely replacing something.

They're not a cassette, the 6-speed Brompton has a 3-speed gear hub with a pair of sprockets, generally 12 and 16 or something like that, those spcokets wear enough with the chain that putting a new chain on a pair of used sprockets will likely not work very well, they're small, they get a lot of crap on them due to the closeness to ground and it's not like a cassette where the wear is spread over 8-11 sprockets.... if you get 4 chains through an 8-speed cassette you would expect to get 1 chain per 2-speed setup....

 

[Fab Foodie]

Even so, you can still get about three chains from a cassette before it needs replacement. I don't see the point in routinely replacing something.

On a regular multispeed cassette, I agree. On the little Brommie 2 speed, I usually change at the sane time. It’s no big deal.

 

[Yellow Saddle]

OK, I get it, thanks Fabs and Chris and Kell. I wasn't aware of this two-sprocket Frankenbike thing.

 

[rogerzilla]

Most chain checkers don't work (they give a false positive). They can't distinguish wear that matters from clearance that doesn't. The Shimano and Pedro's ones are ok.

For a Brompton, I wouldn't bother. The sprockets are cheap so you can just run them into the ground and replace both at once. The chain has to be worn beyond 1/8" per foot to affect the chainring.

On a racing bike with a £150 cassette, you'd change the chain far more frequently.

 

[Banjo]

Thanks for all the replies.I Put the new chain on the old sprockets did a short test ride and it seems fine.

Surprisingly Brompton spares are reasonably priced.The chain was £10 from Evans.I think the pair of sprockets are only another £10 .Unless any slippage occurs I will probably change them when this chain wears to the same extent ie between .5 and .75 wear.

Would like to give the Brommie a decent ride today if it weren't blowing a gale and horizontal rain just now.:-(

 

[berlinonaut]

They do seem to be quite sensitive.

I also change my chainring at the same time every time, but this might actually be overkill.

This seems indeed to be a bit of overkill. Possibly. Some people claim to wear a chainring on a Brompton regularly with every second chain or so while I have never exchanged a chainring on any of my Bromptons due to wear.
Regarding the chain-exchange interval: Personally I think on a Brompton one can deal with it a little bit different from normal bikes: Typically, on a derailleur bike the advice is to change chain and sprockets together and for the interval to follow a chain length checker. The idea behind this ist that a worn chain will kill your sprockets and vice versa and - depending from your bike - the sprockets may be much more expensive than a chain (i.e. with a 11 or 12 speed). With the Brompton on a 2 or 6 speed chain and sprockets are about the same price or - depending from your choice of chain - the chain may even be more expensive than the sprockets. Thus changing the sprockets on a Brompton is not a question of money. On the other hand I've come to "new sprocketes with every second chain" for the time being or, alternatively, "change only when issues like chain falling of or jumping in the higher gear start to show up but then change sprockets and chain". From my experience the Brompton is not too sensitive towards a chain that is shown as "worn" by a chain length checker. And with just one or two sprockets on the rear wheel the financial damage that a lengthened chain could cause is minimal or zero. So I let it run as long as it works flawlessly, no matter what the length checker says. On the other hand I seem to be the opposite of a masher when it comes to chain wear - I exchanged chain and sprockets on my 2-speed this spring, both having more than 4000km on the clock. The chain was worn, but no issues showed up. The sprockets still looked fine and would have been good for another round. Other people need new everything every 1500kms, so the interval seems to be pretty individual anyway.