Search found 3247 matches

by niggle
7 Jan 2020, 11:41am
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

I also concluded that I need around 40-42T minimum for the outer chainring in combination with the 11T sprocket for a decent top gear, but I would like to use the 22T inner, or as small as possible if that won't work, but it seems that if I resolve the problem with the chainring bolt nuts it will w...
by niggle
7 Jan 2020, 11:29am
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

IIRC some MTB chainsets used to be made in which the inner chainring was essentially a repurposed sprocket from a freewheel, so it was steel and held on a centre spline. It might be worth tracking one of those down if you want to use the smallest inside chainrings, although suitable sprockets are n...
by niggle
7 Jan 2020, 10:23am
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

As an experiment, I rode around for a while earlier this year on the road using a crankset with 32-22 chainrings. I used an old Deore XT M737 94BCD crankset, and replaced the outer chainring with a chainguard, leaving the original middle and inner chainrings. Mounted on a 107mm BB, this gave me the...
by niggle
6 Jan 2020, 7:36pm
Forum: Bikes & Bits – Technical section
Topic: Hub Dynamo for winter commute.
Replies: 166
Views: 7097

Re: Hub Dynamo for winter commute.

Just discovered a new offering from Shimano claiming up to 44% reduction in dynamo drag: https://www.spacycles.co.uk/m2b0s133p43 ... H-UR700-3D
by niggle
6 Jan 2020, 6:22pm
Forum: Bikes & Bits – Technical section
Topic: Hub Dynamo for winter commute.
Replies: 166
Views: 7097

Re: Hub Dynamo for winter commute.

At the other end of the spectrum I have a humble Novatec dynamo hub. It is quite heavy and apparently not that efficient (better if you remove the zenner diode which I have done) but it seems solid and both cup and cone bearings are accessible with a bit of care and it seems reasonably well sealed. ...
by niggle
6 Jan 2020, 5:38pm
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

Update: did a 'dry run' with bike on the workshop stand, using two bolts only plus 2x1mm spacer on each bolt to attach outer chainring. Results are mixed, the FD still clears the chainstay by loads and the chain still just clears the bottom and outer edge of the cage in small/small, but only just, a...
by niggle
5 Jan 2020, 6:09pm
Forum: Bikes & Bits – Technical section
Topic: Hub Dynamo for winter commute.
Replies: 166
Views: 7097

Re: Hub Dynamo for winter commute.

@Dim. Supernova do road legal lights Stvzo licenced. The E3 pure 3 https://www.ebay.co.uk/itm/Supernova-E3-PURE-3-Bicycle-Front-Dyanmo-Light-With-Multimount-Bracket-Black-/254118613511?var=&hash=item3b2aa65207 & The E3 pro 2 https://www.ebay.co.uk/itm/Supernova-E3-Pro-2-With-Multimount-Bicy...
by niggle
4 Jan 2020, 5:04pm
Forum: Bikes & Bits – Technical section
Topic: Hub Dynamo for winter commute.
Replies: 166
Views: 7097

Re: Hub Dynamo for winter commute.

@Dim. Supernova do road legal lights Stvzo licenced. The E3 pure 3 https://www.ebay.co.uk/itm/Supernova-E3-PURE-3-Bicycle-Front-Dyanmo-Light-With-Multimount-Bracket-Black-/254118613511?var=&hash=item3b2aa65207 & The E3 pro 2 https://www.ebay.co.uk/itm/Supernova-E3-Pro-2-With-Multimount-Bicy...
by niggle
4 Jan 2020, 4:51pm
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

My wife currently has 40/28 with a 11-34 cassette and I am toying with the idea of trying a 24 smallest ring to replace the 28, giving her a very low spinning gear on long climbs. But before ordering the 24 I will have a look at the current set-up in bottom gear to see if it looks like the rear mec...
by niggle
4 Jan 2020, 12:22pm
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

IME ring spacing is nearer 8mm than 5mm; unless it is made that way the chain rubs in every small-small combination, i.e. no crosschaining rightwards at the back is possible. cheers Did a session of careful measuring (the Spa 104 is currently installed on a steel touring frame with unknown bb, with...
by niggle
30 Dec 2019, 1:23pm
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

Re the chainline issues, road double = 43.5mm, mtb triple = 47.5mm or 50mm, with 5mm ring spacing the chainline of two inboard rings of an mtb triple, used as a double, should be either 45mm or 47.5mm (with recommended BB), if it is 45mm then it may well be possibly to fit a 3mm shorter BB than reco...
by niggle
30 Dec 2019, 12:14pm
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

In your shoes I would weigh up the potential costs of what you are considering doing against the cost of a more 'off the shelf' option, e.g. a Spa Super Compact double. If you already have various other bits and pieces and spares, it should be relatively cheap to experiment with the chainset you've...
by niggle
30 Dec 2019, 9:58am
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

You deserve all the faff that this project is likely to give you … and at the end of it be hankering for a triple. If I had a triple left STI, a road triple front mech and a road triple chainset then maybe, but I don't (actually must check the left STI in case it does have triple capability, but I ...
by niggle
30 Dec 2019, 7:32am
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

No one does an 8 speed 36t cassette? Not even Chinese copies? Cheers James Chinese 11-36t 8 speed cassettes do exist, e.g. https://www.ebay.co.uk/itm/Bolany-11-36T-8-Speed-MTB-Cassette-Steel-Ultralight-381g-Sprockets-Freewheel/283639847504?hash=item420a409a50:g:RFoAAOSwmMVdn9ub To be fair by defini...
by niggle
29 Dec 2019, 2:11pm
Forum: Bikes & Bits – Technical section
Topic: Super compact road double, how low can you go?
Replies: 26
Views: 1137

Re: Super compact road double, how low can you go?

the inner ring can be spaced to the left in order to make clearance for cross-chaining, right up to when the chain will occasionally ride on the tops of the teeth. Whether the chain hits the bottom of the FD varies depending on the seat angle and chainstay angle, as well as the size of the chainrin...