Search found 65 matches

by asinus
26 Jan 2021, 6:41pm
Forum: Bikes & Bits – Technical section
Topic: Hub gear, front derailleur
Replies: 55
Views: 2084

Re: Hub gear, front derailleur

Shimano recommend that the ratio of chainwheel teeth to sprocket teeth should be about 2 or more. The smallest chainring is likely to give you a ratio much lower than this, which runs a risk of stripping sun pinions in the hub from the extra torque applied.
by asinus
5 Jan 2021, 3:40pm
Forum: Bikes & Bits – Technical section
Topic: Converting a deraileur bike to use a Rohloff hub
Replies: 31
Views: 1323

Re: Converting a deraileur bike to use a Rohloff hub

Thanks. Actually, I doubt whether many of the light-fingered community would want to nick a Rohloff as they wouldn't recognize it if it hit them on the head - unless they thought something so bulky was an electric motor . . . but I'd hate to lose it.
by asinus
5 Jan 2021, 10:29am
Forum: Bikes & Bits – Technical section
Topic: Converting a deraileur bike to use a Rohloff hub
Replies: 31
Views: 1323

Re: Converting a deraileur bike to use a Rohloff hub

The advice I'd give is download the manual to find out what you need for your frame to take a Rohloff - and go for it. I had a second-hand hub with a disc, which needed a bit of work to fit into the frame (a late 80s Super Galaxy - see pic). IMG_20190113_135827.jpg It's a bit nervy if you have to wo...
by asinus
29 Dec 2020, 12:10pm
Forum: Bikes & Bits – Technical section
Topic: Steel handalbars
Replies: 10
Views: 699

Re: Steel handalbars

Alloy bars are much more likely to break from fatigue at highly stressed points e.g. abrupt changes of diameter close to the stem - and you may get little warning becuase the crack only grows quickly just before fracture. Steel is unlikely to fatigue at the stress on a handlebar - but if the corrosi...
by asinus
29 Dec 2020, 12:04pm
Forum: Bikes & Bits – Technical section
Topic: Rear derailleur for 6-speed freewheel
Replies: 5
Views: 326

Re: Rear derailleur for 6-speed freewheel

Old flat bar-mounted Shimano thumb shifters had a lever that enabled a switch to friction mode, which can be useful if your block hasn't Shimano-compatible spacing.
by asinus
29 Dec 2020, 11:58am
Forum: Bikes & Bits – Technical section
Topic: Pashley rear wheel
Replies: 15
Views: 590

Re: Pashley rear wheel

For replacing the spoke, the tool you need is the Spocalc spreadsheet on the Sheldon Brown site, if you can measure the hub and rim, to get the right length.
by asinus
12 Nov 2020, 9:34pm
Forum: Electric bikes
Topic: Panniers that fit onto battery racks?
Replies: 4
Views: 285

Re: Panniers that fit onto battery racks?

My wife had this problem, but sorted it out with an extra rack that fitted on top of the battery rack, bought from Wisper (Wisperbikes.com) - it's Dutch, not purely for e-bikes - a bit of a faff to fit, and extra weight, but it does the job.
Wisperrack.jpg
by asinus
14 Sep 2020, 9:52pm
Forum: Does anyone know … ?
Topic: SAMEBIKE L026 (folding e-bike 500 watt)
Replies: 4
Views: 363

Re: SAMEBIKE L026 (folding e-bike 500 watt)

A 500W motor will take twice as much juice as the 250W road-legal maximum, and so if ridden on full power a small battery might run out after not very far - how many Ah is the battery, and what is the voltage (multiplied, they give the total energy stored in Watt-hours)? On the principle that you ge...
by asinus
14 Sep 2020, 9:44pm
Forum: Does anyone know … ?
Topic: Northern rail folding bike options?
Replies: 18
Views: 608

Re: Northern rail folding bike options?

I'm 6'5" or so, and have a 26" folder - an ancient Phillips (Dahon rebadged), which does just about fit in the new Northern rolling stock without obstructing the gangway too much on a train that isn't crowded. The seatpost is at the max and the reach shortish, and so I'm not sure that you'...
by asinus
24 Jan 2020, 8:28pm
Forum: Bikes & Bits – Technical section
Topic: Swarf from rim
Replies: 9
Views: 547

Re: Swarf from rim

Thanks all. Fortunately things are nowhere near bad enough to worry about rim thickness - that's what I'm trying to avoid before it's too late. I've ordered some Koolstop blocks, and have done the other things advised. The rims were indeed machined, which I guess could initiate the problem (though t...
by asinus
23 Jan 2020, 11:26pm
Forum: Bikes & Bits – Technical section
Topic: Swarf from rim
Replies: 9
Views: 547

Swarf from rim

One side of my front rim (Ryde Sputnik, a year old) is continually shedding swarf into the brake block. The other side did so when new, but I've had little further trouble since I changed the blocks for ones I thought were softer, and rubbed the rim gently with fine abrasive paper. I've dug the meta...
by asinus
12 Jan 2020, 7:52pm
Forum: Electric bikes
Topic: Couple of newbie questions.
Replies: 11
Views: 764

Re: Couple of newbie questions.

P.S. Should have said that what matters about the motor, if putting force through your foot is the problem, is the Torque it delivers, i.e. the turning force it develops - the more, the better. Since power = torque x speed of rotation, you'd just be losing top speed (but then, the motor has by law t...
by asinus
11 Jan 2020, 6:23pm
Forum: Bikes & Bits – Technical section
Topic: Sachs Super 7/Sram Spectro S7 hub; No Future?
Replies: 15
Views: 1895

Re: Sachs Super 7/Sram Spectro S7 hub; No Future?

I rode one for about five years till I wrecked it by forgetting to fasten the reaction arm for the back-pedal brake after a tyre change (doh). I was very happy with it - only once mis-behaved - on a Saturday afternoon in rural Northumberland - but soon sorted itself out. Changing the cable at the cl...
by asinus
11 Jan 2020, 5:55pm
Forum: Electric bikes
Topic: Couple of newbie questions.
Replies: 11
Views: 764

Re: Couple of newbie questions.

Important to distinguish power from force : I guess your foot hurts if you put too much force/weight on it: power is the rate of doing work, which is different, and only partly relevant to your problem. You could minimize the force you put through your painful foot by (a) using a cadence-sensor bike...
by asinus
26 Nov 2019, 4:28pm
Forum: Bikes & Bits – Technical section
Topic: How do I tighten this bottom bracket?
Replies: 15
Views: 1115

Re: How do I tighten this bottom bracket?

Update: I took the chainring off, and it seems that it also engaged with more splines co-axial with the BB axle, which presumably connects it to the torque sensor inside. The play presumably comes from there, so I doubt if it matters - the chainring itself doesn't show signs of wear where it engages...