# Chain wear checker for a Brommie.



## Banjo (27 Sep 2019)

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.


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## fossyant (27 Sep 2019)

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


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## Banjo (27 Sep 2019)

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.


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## mitchibob (27 Sep 2019)

Banjo said:


> 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.


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## Yellow Saddle (27 Sep 2019)

mitchibob said:


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



Why?


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## Kell (27 Sep 2019)

They do seem to be quite sensitive.

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


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## Fab Foodie (27 Sep 2019)

Yellow Saddle said:


> 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


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## Yellow Saddle (27 Sep 2019)

Fab Foodie said:


> 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.


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## Kell (27 Sep 2019)

Yellow Saddle said:


> 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.


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## chriscross1966 (27 Sep 2019)

Yellow Saddle said:


> 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....


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## Fab Foodie (27 Sep 2019)

Yellow Saddle said:


> 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.


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## Yellow Saddle (28 Sep 2019)

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


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## rogerzilla (28 Sep 2019)

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.


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## Banjo (28 Sep 2019)

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.:-(


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## berlinonaut (28 Sep 2019)

Kell said:


> 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.


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## Kell (28 Sep 2019)

As I say. I tried to get too much out of a previous chain and it left me physically and financially worse off. 

An estimated three months off the bike at the current rate of £7 a day for the tube plus £9.40 for parking, five days a week. Is £328. That’s three and a half years’ worth of full drivetrain replacements.


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## rogerzilla (28 Sep 2019)

My rule of thumb for a derailleur bike is that one chainring should last three cassettes and nine chains, if the chain is changed in time (at 1/16" of extension per foot). But for a Brompton or anything with cheap sprockets, I'd run the chain twice as long and replace the sprocket at the same time. On fixies, some people run the whole lot into the ground as the chain won't slip or suck even if all the teeth look like shark fins.


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## Yellow Saddle (28 Sep 2019)

rogerzilla said:


> 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.



1/16th per foot. Over that and you've exceeded the designed wear limit and it eats sprockets.


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## Yellow Saddle (28 Sep 2019)

Can someone perhaps post a photo of a Brompton (the one in question type) side-on view of the rear hub area. I want to understand something about these. I've never seen one in the flesh.


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## rogerzilla (28 Sep 2019)

Yellow Saddle said:


> 1/16th per foot. Over that and you've exceeded the designed wear limit and it eats sprockets.


I agree for the sprockets but the chainring can cope with a more worn chain before it suffers unduly.


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## Banjo (28 Sep 2019)

Yellow Saddle said:


> Can someone perhaps post a photo of a Brompton (the one in question type) side-on view of the rear hub area. I want to understand something about these. I've never seen one in the flesh.


I will post some pictures but it will be later on today.


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## Kell (28 Sep 2019)

I think next time I do a full chain and sprocket change i’ll Just rotate the chainring so the teeth under load are not in the same place. 

I was unsure if this could be done because of the reverse fixing on the crank, but looking at the one i’ve Just taken off, it’s doable. 

(The rounded spoke is bottom left instead of top. This was just to check if it would fit back on the crank. Would probably need it to be a quarter turn. )

Would save £25.


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## Banjo (28 Sep 2019)

Not a great picture sorry.


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## Yellow Saddle (28 Sep 2019)

Banjo said:


> View attachment 486906
> View attachment 486906
> 
> Not a great picture sorry.


Thanks, but that doesn't help. 

90 degrees and in-line with the axle. Use the focus feature on your camera,


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## Banjo (28 Sep 2019)

Or use a real camera instead of the crappy one on my cheap phone.The stainless steel shoe thing to the right of the axle moves the guide wheel in or out shifting the chain onto the large or small sprocket.


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## Yellow Saddle (28 Sep 2019)

Thanks, that's good. One more thing. How many teeth on that sprocket?


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## Banjo (29 Sep 2019)

Yellow Saddle said:


> Thanks, that's good. One more thing. How many teeth on that sprocket?


My bike is the standard ML6 with 13 and 16 teeth sprockets. And a 50 tooth chainring.

You can order the bike with higher or lower gearing.


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## Yellow Saddle (29 Sep 2019)

Banjo said:


> My bike is the standard ML6 with 13 and 16 teeth sprockets. And a 50 tooth chainring.
> 
> You can order the bike with higher or lower gearing.


Thanks.


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## mitchibob (30 Sep 2019)

Yellow Saddle said:


> 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.



But nothing like as close to the ground and picking up so much crap. The only time I tried to change chain without changing sprockets, the first time I went up a 1% gradient, the chain slipped on every turn of the cranks. Was the night before a sportive and ended up putting the old chain back on as I'd left it too late to find sprockets.

Sprockets are very cheap and quick to change.


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## berlinonaut (30 Sep 2019)

mitchibob said:


> But nothing like as close to the ground and picking up so much crap.



I can highly recommend using a better (longer) mudflap than the stock one on the front wheel. With the stock one dirt and water gets thrown directly onto chainwheel and chain (as well as water onto your feet), with a longer one none of this happens any more. With drastic positive effects on chain life (as well as on the dryness of your feet when you ride in the rain). With readers of the German Bromptonauten-forum the "Fahrer Latz Race" is close to become a standard on the Brompton to the same amount as Ergon Grips are. Both are a drastic enhancement over the factory standard. Obviously it is easy to build a longer mudflap yourself from surplus materials - give it a try.


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## Kell (30 Sep 2019)

An


berlinonaut said:


> I can highly recommend using a better (longer) mudflap than the stock one on the front wheel. With the stock one dirt and water gets thrown directly onto chainwheel and chain (as well as water onto your feet), with a longer one none of this happens any more. With drastic positive effects on chain life (as well as on the dryness of your feet when you ride in the rain). With readers of the German Bromptonauten-forum the "Fahrer Latz Race" is close to become a standard on the Brompton to the same amount as Ergon Grips are. Both are a drastic enhancement over the factory standard. Obviously it is easy to build a longer mudflap yourself from surplus materials - give it a try.



And it's the Race version, not the urban version that works?

Any pictures of one fitted to a Brommie? I'd certainly be interested in something which work a little better.


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## berlinonaut (30 Sep 2019)

Kell said:


> And it's the Race version, not the urban version that works?
> Any pictures of one fitted to a Brommie? I'd certainly be interested in something which work a little better.



Yup - the race is slimmer and it works like a charm on the Brommi.
Here's the silver version:





Herre's the black version:




in detail:




compared to the original:


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## Kell (1 Oct 2019)

Thanks for that.

Just ordered one.


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## berlinonaut (1 Oct 2019)

Kell said:


> Thanks for that.
> 
> Just ordered one.


The best way to mount it is if you arrange the Latz and the original flap as in my picture above an copy the position of the holes from the original to the Latz. Fahrer Berlin delivers it with zip ties for mounting but on the Brommi using the original mounting points works best and looks better as well.


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## Kell (6 Oct 2019)

berlinonaut said:


> compared to the original:
> View attachment 487245



Ok. So mine arrived and I fitted it yesterday, but there’s no way it was as long as the above.

By lining up both of them at the top edge, the Fahrer logo was completed covered.

It was only about a cm longer than the original.

So I moved it down a fair bit to fit it. But in doing so, I did wonder if anyone’s tried remounting their original one further down? This would give the additional length, but also offer some extra width.

May not be necessary, but that slimmer design looks better, i’m Just concerned about spray coming out to the sides.

What I can say is that I fitted a brand new chain, chain ring and sprockets last week and they were covered in ‘bits’ this week. It’s rained pretty much every day, presumably this crud was thrown up from the front. So hopefully this will prevent that.

We’ll see.


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