Supercommuter?

For discussions about bikes and equipment.
Brucey
Posts: 37288
Joined: 4 Jan 2012, 6:25pm

Supercommuter?

Postby Brucey » 28 Nov 2012, 12:01pm

thought I'd share a few details of a recent bike build I did for a chum of mine;

My chum (who also has a nice road bike and a touring/audax bike etc) commutes about eight miles a day wearing street shoes, is happy with battery lights (he knows about hub dynamos because that is what the missus has BTW), likes relatively closely spaced derailleur gears, doesn't buy into the whole 'fat tyres are faster' thing, quite likes his mudguards set close (he stays cleaner) and wants to do as little maintenance as possible.

The previous bike lasted about 15 years before the chainstays rusted right through. Almost every single component on that bike was worn or rusted badly and was at the end of its life. I commented that if Colin Chapman had designed a commuting bike, it would be like that; at the end of its life, every single part about to fail simultaneously.

The old bike even had the non visible rim eyelets corrode away to nothing inside the rim. :shock:

This is the new bike I built.

DSCF2444v5.jpg


The wheels have aluminium SA hub brakes (which have some of the smoothest bearings of any hub IMHO), DT DB spokes, Mavic Open sport rims (single stainless eyelet), conti gatorskins.
The frame is a Raleigh in reynolds 501. SKS mudguards with stainless fittings.
The transmission is a simple, robust 6s indexed one, with a galvanised chain. The idea is that the consumables are cheap and durable. The screw-on freewheel has 14,16,18,20,24,28T and there is a 44T chainring (chainguard to be added). It is not very hilly round here so the gears have an adequate range.
Punctures are not part of the plan, but the wheels might have to come out in a hurry. The brake levers have a QR button, which allows the brake cables to be unhooked at the hub end in seconds. The front wheel can be removed in 15s and the rear in about 30 (there is not yet a QD ftting on the reaction arm of the rear brake).

There are a whole load of special adjustments, fittings and adaptations. The frame is internally treated with waxoyl, and the vent holes are blocked. The outside of the frame is coated in clear plastic film in key places to deter corrosion and prevent damage from locks etc.
The seat post and the stem have additional seal rings added to stop water ingress.
The 130bcd chainring is meant for 1/8" chain, but has been remachined so that 7s chain is 'just snug' on it which should mean a longer life and no derailments. The rear hub is upraded to 2RS bearings, waterproof grease, and the freewheel has custom -made seals front and back that can be re-used with replacement freewheels. The present freewheel is a sunrace one, which needed reshimming from new, but has slick-shifting HG style sprockets.
The UN52 BB unit has a lube port added to it and is packed with Castrol SBX grease (which is 'the right grease' IMV), the pedals have lube ports too.
The rear mech is a light action 'preselect' type one, and the jockey pulley bushings are fitted with lube ports. I have found that these rear mechs (like any other) can bend in a crash, but (unlike many others) they can nearly always be bent back again, because the parts that bend are made of steel. The shift quality is very good indeed, probably the best 6s shift I have ever used.

The rear carrier is mounted using blackburn-style (but custom-made and therefore more snug/stronger/better) dropout adaptors.

Needless to say every fitting that could be was stainless steel and everything else is corrosion-proofed and/or treated with copper-ease or waxoyl where it is fitted to the frame. There are glint-tape patches on the frame for added night-time visibility.

I road tested the bike (less mudguards, rack , with different pedals/rear mech) and it rode very well. Only weighed about 25 1/2lbs, too. Although the weight went up in the final spec, it goes very well. In fact it goes so well, the gearing might need to be revised; the 44/18 gear was meant to be the most used, but I am told that thus far, it has more often been the next one up.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

robc02
Posts: 1683
Joined: 23 Apr 2009, 7:12pm
Location: Stafford

Re: Supercommuter?

Postby robc02 » 28 Nov 2012, 3:43pm

Its nice to see drum brakes on a bike like this :)
(says he who has just built his own "supercommuter" with rim brakes :oops: )

Why did you opt for SBX grease instead of LMX? (I ought to find out more about lubricants; I tend to buy whatever is available in my local motor factor!) I'd like to find a suitable runny grease or thick oil for injecting into pedals and BBs - runny enough that it finds its way around but not past the seals.

Brucey
Posts: 37288
Joined: 4 Jan 2012, 6:25pm

Re: Supercommuter?

Postby Brucey » 28 Nov 2012, 3:53pm

robc02 wrote: Why did you opt for SBX grease instead of LMX?


IIRC SBX has a higher base oil viscosity, solid lubricant additives etc, so is meant to be better for low speed/high load running. (oh, and I have a big drum of it.... :wink: ).

A semi-fluid grease is often quite a good idea for some sealed components; the stuff that is used in land rover swivels is pretty decent. I used a large dollop of semi-fluid grease behind the outer freewheel seal on this bike, and it is staying inside thus far, where I'm sure an oil would've leaked out.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Ayesha
Posts: 4192
Joined: 30 Jan 2010, 9:54am

Re: Supercommuter?

Postby Ayesha » 28 Nov 2012, 6:36pm

Nice.
Takes me back a couple of decades.

Must say,,, front splash flap is a bit short. The chain set, BB and rear mech are gonna get soaked.
It needs to be a length of rubber sheet pop-riveted to the front guard.

Pls report back on the effectiveness of the SA hub brakes. Are they Far East manufacture?

Brucey
Posts: 37288
Joined: 4 Jan 2012, 6:25pm

Re: Supercommuter?

Postby Brucey » 28 Nov 2012, 7:34pm

I agree the front mudflap is a bit short; the mudguards and the rack were pretty much the only parts from the previous bike that could be re-used; they didn't get too much special treatment.

The brakes on the commuter have yet to bed in, so don't have full power. They seem to be compatible with the road brake levers even though they don't have a very long cable pull. Unlike a rim or disc brake, the 'bite point' can be set to that there is no drag, or rubbing, but brake starts to come on almost immediately the lever is pulled. I'd say that in the case of the rear brake, it needs to set this way; the cable housing is quite squishy, so about half the lever travel can be used up in cable housing compression with the standard cable outer. It might well be that the brake could be improved with better cable outer.

I've got similar brakes on my Pashley which should be fully bedded in (they are about fifteen years old...) and they stop the bike quite quickly; from flat out (about 20-25mph ) to a full stop is about four or five metres (this is with an all-up weight of about 250lbs, and no, I'm not breaking that down.. :oops: .). It was a little bit longer than that, until I did a modification to the front brake which allows the brake force to be more evenly distributed. The difference between these hub brakes and disc or rim brakes is that with the hub brake, it comes on immediately, and the brake force (for a constant pull) doesn't seem to vary so much during the stop. Both disc and rim brakes usually don't come on hard as soon as the lever is pulled (especially in the wet) and also tend to come on (or off) somewhat during any one stop at constant pull force. With the best disc brakes I have, in the dry, I can stop only slightly more quickly than with the drums, even though it is obvious that the peak braking force is a good deal greater with the discs. With average disc brakes, it is cartainly no better than with the drums. In the proper wet, nothing comes close to the drums.

I also have some XL-FD (90mm) brakes to try; these offer more power. I've not used them yet, but I'm told that stoppies are on with these, where with the 70mm units you would struggle to do this.

I can't see or feel any significant difference between the Taiwan-made SA brakes and the Nottingham produced ones I have used. If I am critical, I'd say that new brakes need a smear of lube on the cam, and the bearings could do with more grease in them and (at the rear especially on the X-RD hub for threaded freewheel) better seals.

The drums are not 100% weatherproof; if I leave the bike for a week or so in the damp (in which case the drums get a superficial rust coating which gives more bite than normal at first) or outside leaning rightwards and it rains, a small amount of water can get into the drums and the first stop of the day is affected. Maybe if the power needs to be varied during a long stop, the modulation of drums is less sensitive than with some other brakes. But really I'm splitting hairs.

After nearly fifteen years my front brake hub needed fresh grease in the bearings, and the shoes turned out to be about 1/3 worn; (BTW, you can check for brake shoe wear from the outside in about ten seconds, simply by judging free lever arm movement with the cable disconnected). It isn't that hilly round here so I'd expect a low wear rate; but even so, I've never heard of anyone wearing a set of shoes out on a solo in much less than five years. IIRC when they approved the linings for GPO use they reckoned they would last several years of postie-(ab)-use, and do so. If the bearings were to fail, I reckon they could be changed in less than an hour, and they are not expensive.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

mig
Posts: 2156
Joined: 19 Oct 2011, 9:39pm

Re: Supercommuter?

Postby mig » 28 Nov 2012, 8:17pm

very nicely executed commuter cycle!

you bike is however rather on the heavy side for my own tastes....!

Steveo2020
Posts: 215
Joined: 26 Apr 2012, 8:57pm

Re: Supercommuter?

Postby Steveo2020 » 28 Nov 2012, 9:19pm

Nice work! Thanks for posting.

A couple of questions if I may:

1. Where do you drill the bb for grease injection? Are they difficult to drill?

2. What did you use to seal the seat post and stem?

I bought a generator hub for my bike a few years ago and regret not fitting a drum brake - my commute is hilly and cantilevers are a nuisance to keep adjusting.

Cheers

Brucey
Posts: 37288
Joined: 4 Jan 2012, 6:25pm

Re: Supercommuter?

Postby Brucey » 28 Nov 2012, 10:22pm

shimano UN BB units are nigh-on impossible to drill conventionally. My method is to grind through the housing, carefully, until the remaining wall is paper-thin (which you can tell because it will be glowing red-hot), then punch through using a centre punch. This minimises any debris inside the BB unit. The unit is then filled/purged with high quality grease using a grease gun with a pointed nozzle, and the then the hole is simply taped over with a few turns of insulating tape. In order for the lube to be topped up/purged, the BB unit needs to come out of the frame; if I were cleverer I'd have 'timed' it so that I could access the hole from the outside somehow. At least regular removal means the BB unit isn't going to seize in the frame I suppose, although I don't think it will need to be serviced more than once every year or two.

The stem and seat pillar seal rings were cut from heavy duty (~1mm thickness) weatherproof polyethylene sheet material using 22.0 and 26.0mm wad punches respectively. The material will stretch slightly so a 27.0mm seat pin will enter the 26.0 hole. The stem seal ring is similarly snug around the stem, and a little sealant is used between it and the locknut. Water cannot enter in the normal way. The seat post seal ring is similarly attached to the seat post. Conveniently the frame has a flat top to the seat lug; a scalloped one would have made this seal ring less useful. The seat pin seal is shaped on the outside so that it has a 'tail' that covers the binder bolt etc, so that water is less likely to enter there, too. I think I have photos of these somewhere, I'll post them if I can dig them up. Both are rather unobtrusive; you don't notice them at first.

cheers



cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Steveo2020
Posts: 215
Joined: 26 Apr 2012, 8:57pm

Re: Supercommuter?

Postby Steveo2020 » 28 Nov 2012, 10:39pm

Thanks Brucey - the seal rings sound like a neat idea. A pic would be great if you have one to hand.

Interesting re the bb - I thought drilling would not be simple - maybe one day I will try the grinding method!

Cheers

Brucey
Posts: 37288
Joined: 4 Jan 2012, 6:25pm

Re: Supercommuter?

Postby Brucey » 28 Nov 2012, 11:58pm

seal rings;

seal ringsv2.jpg


with apologies for poor image quality.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Ayesha
Posts: 4192
Joined: 30 Jan 2010, 9:54am

Re: Supercommuter?

Postby Ayesha » 29 Nov 2012, 7:43am

Can you post some piccies of how the hub reaction arms fix on the forks / stays..

Cheers for this. Winter project in planning.

mig
Posts: 2156
Joined: 19 Oct 2011, 9:39pm

Re: Supercommuter?

Postby mig » 29 Nov 2012, 10:45am

from what i've read 'glint tape' only shines when viewed through night vision equipment? or are there different types?

Brucey
Posts: 37288
Joined: 4 Jan 2012, 6:25pm

Re: Supercommuter?

Postby Brucey » 29 Nov 2012, 11:09am

Re the glint tape; I've seen the stuff I used sold as such (with a 'visible caveat') so possibly I have misued the term in the strictest sense then; I don't use night vision equipment (and nor do local motorists... :roll: )

Re the brake arms; there are clips that are bolted round the fork and the chainstay respectively. The front clip has a slot in it, so the reaction arm tab just slides in to the slot. Once the cable is unhooked, ( a finger job) the front wheel is free to just drop out. If the clip is positioned in the right place, when the wheel is replaced, the tab starts in the slot before the axle starts in the dropouts, whereas if the clip is set slightly higher, everything has to start at the same time which makes replacing the wheel rather more awkward.

At the rear, the bolt that fixes the clip to the frame also passes through the reaction arm, so it needs to come out before the reaction arm can be released. I think it is done like this because most SA rear brakes are attached to an IGH; the wheel is usually adjusted horizontally in the dropouts, and indeed might slip in that direction if the track nuts are not done up properly. If the reaction arm might come adrift when this happens, or when the chain is adjusted, that would be a very bad thing. The gain in making a QD reaction arm for a typical IGH rear wheel (with gear controls, chaincase etc) is small, so presumably not worth any risk. With derailleur gears (not to mention vertical dropouts if you had those) things would be different.

BTW my Pashley has braze-ons for both reaction arms, but the rear one still has a bolt going through it.

I'll post some pictures later if I get the chance.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

robc02
Posts: 1683
Joined: 23 Apr 2009, 7:12pm
Location: Stafford

Re: Supercommuter?

Postby robc02 » 29 Nov 2012, 1:40pm

The brakes on the commuter have yet to bed in, so don't have full power. They seem to be compatible with the road brake levers even though they don't have a very long cable pull. Unlike a rim or disc brake, the 'bite point' can be set to that there is no drag, or rubbing, but brake starts to come on almost immediately the lever is pulled. I'd say that in the case of the rear brake, it needs to set this way; the cable housing is quite squishy, so about half the lever travel can be used up in cable housing compression with the standard cable outer. It might well be that the brake could be improved with better cable outer.


I had a similar situation with a rear drum operated by a road lever - a '90s Camapag model that could be used standard or aero (with the aid of a small insert to turn the cable through 90 degrees). I replaced the levers with some Tektro ones for V 'brakes. This solved the "squishyness" and, despite the lower MA, left plenty of power and good "feel" - though I have modified the brake to have a floating cam.

I have seen a bike with bare cable from the head tube to the brake, running under the BB in a derailleur cable guide. This also worked well, but I would only be fully happy with it if the frame had vertical dropouts or perhaps rear facing dropouts and a chain tug to prevent the wheel from moving forward.


Regarding BB lubrication ports - I have a Campag unit with an aluminium sleeve. I plan to drill it, probably at the same time as I drill the BB shell, so that the holes line up and I can inject lubricant without removing the BB unit. Hopefully, if it becomes necessary to remove and refit the unit the holes can be lined up and held in position by a rod or screw before finally tightening the fixed cup. I have yet to get around to doing this and I can see one or two potential pitfalls, but I'd like to give it a try at some point.

Brucey
Posts: 37288
Joined: 4 Jan 2012, 6:25pm

brake reaction arm fittings

Postby Brucey » 29 Nov 2012, 3:00pm

as promised. BTW 'orrible black stuff on Pashley is it's 'winter coat'; Waxoyl.

DSCF2459v3.jpg


DSCF2461v3.jpg


DSCF2460v3.jpg


If the supplied clips are the wrong size for the frame, some packing with tape is OK, plus there are other diameters available also.

The reaction arm bolt is a bit of a 'Jesus Bolt' (ask a pilot). Some form of locking on it is more or less essential for safety.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~