Metal Chain Guard for a Brompton

Nearly everything on my Brompton bicycle is just about perfect, but there’s no denying that Basil’s chain guard does not represent Brompton’s finest hour.


Basil is a 2012 Brompton; his chainguard is plastic, or a nylon-like plastic, or something of the like.  It’s held in place, more or less, with rivets of the same material, which mate to the metal chain ring.

I say “more or less” because the rivets wear, which causes the guard to warp slightly, which allows the guard wires on the wheel to catch every now and then, and, eventually, the chain guard pops off and is rendered useless.

When the rivets on Basil’s original guard popped, I had NYCeWheels replace it, though it seemed obvious that the replacement was likely to exhibit exactly the same fault.


As expected, it wasn’t long until the new plastic guard began to warp.  You may or may not be able to make out the beginning of the end in the image above.

I procrastinated long enough that eventually Mr. Orange posted a solution to this vexing problem.  He replaced the original guard on his orange titanium Brompton with a metal one from Tiller Cycles in the UK.


Tiller makes the chain guards (click on the section called “Brompton Bling“) in a wide range of Brompton colors and in two non-coated variations.  My inclination was to go for black, stainless or aluminium, but Dr. Diarist suggested that I really should match Basil’s Brompton yellow.

cg-pgThis seemed a bit much, but, on the other hand, Mr. Orange’s Brompton did look quite nice with its new ornament, so I sent off for one in Basil’s frame color.  It arrived quite promptly, neatly attached to a piece of cardboard.

cg-cmThe Tiller guard is just marginally larger than the original, but the mounting points match perfectly.

Installation (and removal from the backing) was facilitated, naturally, by Brompton’s sweet little ratchet set.


Tiller’s note reminds customers to set all the bolts before tightening, and I remembered, from years gone by, to tighten every other bolt in order to keep stresses even while going along.

Stainless spacers hold the guard away from the chain.


I sensibly used thread locker during installation, and I’ll remember to check the bolts now and then just to make sure that they stay tight.


When the bicycle is folded, the fold guard wires do make contact with the chain guard, so I expect that the pristine beauty of that paint job may not last.  From that standpoint, the polished stainless or aluminium may have been the better choice.  We shall see.


However, unlike the original guard, this one is unlikely to deteriorate in the course of ordinary use, and should not warp over time.

cg-nwThe new guard is a thing of beauty, and the color match perfect.

Basil, as he originally appeared:


And newly ornamented:


Basil is not as conservative as I am, and appears to be quite pleased with both the practical and aesthetic aspects of this change to his armature.

For those of us in North America, this is a costly bit of kit, particularly as postal rates are extraordinarily high — nearly the price of the guard itself.  (UK customers will presumably find the price to them more palatable.)  However, I expect the purchase to prove to be a good one, and I am relieved that I am no longer continually watching the original guard and wondering when it will finally fail once more.

There is a great deal to be said for having solved a nagging problem once and for all — and, of course, the expense of Basil’s flash new trim can reasonably be offset by what each new plastic replacement might have cost.

It has crossed my mind that Argyll might look quite smashing with a sage green guard; however, he is a 2013 Brompton, and his own chain guard is screwed firmly on, Brompton having addressed the issue, as they do, ongoing.  Argyll will have to argue his case on aesthetics alone, rather than practicality.  We will see what Dr. Diarist says to that .  .  .

34 replies on “Metal Chain Guard for a Brompton”

By the way, good choice on the polished stainless. It will be perfect on Maggie, and probably look great forever. (I’m really curious to see exactly how well the paint endures. I have my suspicions . . . )

rim shot, Mme. Diarist and perfect set-up Cathy

You could probably get an appropriately colored and sized rubber tube, slice it and place it over the offending guard wires.

Oh, good idea, Saul! I’ll have to find something with very thin walls, though, as there’s little clearance. May have something in the basement, in transparent tubing. Then the trick will be trying to get it to stay on — but this might just work!

It’s harder to count teeth on a Brompton chainring than on an uncooperative Maine Coon. I’ll have to call NYCeWheels and ask, to Peter’s amusement, no doubt.

Not to undercut Peter’s opportunities for amusement, but try putting a bit of tape beside tooth number one, and counting round from there. I matched the shape of Basil’s existing guard to one on the Tillis site, then correlated the year, and that worked for me — but I think there was no ambiguity for Basil’s model year (2012).

Counting teeth on a Maine Coon? Oh, please, let me never have the experience!

I didn’t know that, Saul. No marking that I can see on Basil’s, at least.

Duct tape is an idea, but I don’t know. I’m using it on Basil, but it’s hidden in his seat sstem. I’m not too sure he’d approve, what with duct tape’s reputation for being a quick-and-dirty repair. I do have helicopter tape, widely used to protect areas of friction, and it’s transparent. Maybe I’ll try that first, though usually it’s applied to the painted surface — an approach that isn’t really practical here. Hmmmm . . . time to do some experimentation.

Dr. D does indeed know his MCs. I got Mack to pose in a hand-knit hat once, and lost no skin in the process, but that’s as far as I’d push him.

Fortunately, counting my Brompton’s teeth was painless, thanks to Brommie’s suggestion. Fifty!

In general, I find Bromptons far more willing to pose than Maine Coons, but, then, I’ve never tried to put a hat on Basil . . .

I’m glad marking the tooth did the trick!

Hmm… (ponders whether any possible response can be made to the recent conversations but decides the lack of MCs is the limiting factor?) Back on the topic (briefly?), I await any in-use comments on Tiller’s excellent guards with some interest although the original guards on my older Bromptons are holding up well (with just the occasional prodding back into place). I feel that the warping isn’t significant & comes from the flexing of the plastic under pressure applied during the fold (hopefully that pressure won’t spoil the surface of your new guards?). Using the non-permanent version of thread locker is sensible but be cautious of regular re-tensioning of the bolts to avoid “cracking” the seal.
Apologies for possibly diverting the conversations.

Ian, could a brace of Maine Coons be the Brompton accessory you need now? (Something to ponder!)

So far so good with the Tiller guard — and, for that matter, not a mark on it yet, despite at least a dozen folds since installation. After due consideration, I wrapped the fender arm with helicoptor tape; we’ll see if that prevents any ontoward scratches going forward.

You’ve either got better guards than Basil got, or you are a lot less clumsy; once Basil’s warped a bit, I kept catching them, either with a shoe, a cuff, or with the fold hook. At that point, his were doomed.

Thanks, Ian, for the reminder about the thread-locker; I’ll keep it in mind when checking for loosening, and use a delicate hand!

24 comments, including this commentary, may be a record….just sayin’. Who would think a chain guard would generate such interest? Teeth, color coordination, polished metal, cats, drum rolls and rim shots.

The written acknlowledgment of the denial of the temptation to reply is nonetheless a reply. Hence, we now have #25 and #26.

…and may I say that the new chain guard is the perfect completion, to this point, of Basil’s handsome ensemble. Good luck to Basil in the primary election.

That Saul, here he goes again! Throwing in a curve ball to redirect the conversation? (sorry if it’s only me that has missed the point of Saul’s last comment & maybe I should stand by idly & await developments?)
No, I think the chain guard deserves the limelight of the conversations. It’s an “unsung hero” for a functional part of a Brompton (another of those subtle aspects to Brompton engineering). As a dedicated bare-leg rider I have often taken advantage of the chain guard when standing astride any of my Bromptons, by being able to support the bike hands-free by resting my right leg against the frame & never having to worry about that non-folder affliction; the greasy tattoo. For those who ride their Bromptons with flapping leg coverings, I suspect they give little thought to how the chain guard eases their laundry concerns? The chain guard gets my vote (if that helps Saul in some way?)

Not only you, Ian, but others too: Saul made an interesting discovery on Sunday’s group ride. Today’s blog post explains all.

Love your eloquent and comprehensive ode to the chain guard — I’ll never take Basil’s (whether original or custom) for granted again! But now, a quandry: Does one vote for Basil, or for his chain guard???

Considering the magnitude of the electoral process I would be willing to switch my vote! In fact, Basil would get my vote even if he were naked. (There you go; my support for you to start stripping Basil (temporarily) for your tilt at BNC glory?)

Oops, apparently I am still commenting after all! Basil’s delilghted to have your vote, Ian, in whatever condition he finds himself, but you raise a good point: Hmmm, how seriously to take the BNC? And could the presence, or not, of his saddle bag, for instance, really make a difference, considering the slow stately progression of his rider?

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