Search found 1748 matches

by robc02
19 Sep 2021, 10:01am
Forum: Bikes & Bits – Technical section
Topic: Drum brakes
Replies: 38
Views: 1379

Re: Drum brakes

rotavator wrote: 19 Sep 2021, 9:37am How do drum brakes perform on long descents with a load on board e.g. on the long descents on Lon Las Cymru? Are they any better or worse than rim brakes or hydraulic disc brakes or are cable operated disc brakes the best option? I would imagine that drum brakes get very hot and start burning any grease or oil that is near them but do they also fade or squeal?
I have ridden Lon Las Cymru (south to north) on a bike with SA drum brakes without problem. Certainly no overheating or squealing.
I have subsequently ridden on my LHT with cantilevers. Again no problems, either with stopping or overheating. The braking was a bit better with cantis than with drums.

In each case I was carrying camping gear. However I am around 63kg, so even with the weight of my luggage I am not a demanding load on the brakes!
by robc02
15 Jul 2021, 12:05pm
Forum: Bikes & Bits – Technical section
Topic: A tale of three bikes.
Replies: 36
Views: 1377

Re: A tale of three bikes.

mig wrote: 15 Jul 2021, 11:29am

totally agree. it's mainly position on any bike. yes that's aerodynamics but also how able you are to exert force through the pedals and how much/little fatigue that position generates over time.

three contact points. getting them right is the main determinant of how well you go.
Yes, and I'm pretty obsessive about getting my position the same on all of my bikes - well on my "roady" ones anyway. My LHT has its bars approx 10 mm higher than the others, but the saddle height and back/forth is the same. I suspect I bend my arms a bit more to compensate, especially when I am trying hard.
by robc02
15 Jul 2021, 10:55am
Forum: Bikes & Bits – Technical section
Topic: A tale of three bikes.
Replies: 36
Views: 1377

Re: A tale of three bikes.

Anybody else reassessing their old steel frames?
I've posted this elsewhere on the forum in the past.

I have done multiple back to back comparisons of my Principia Rex Sx and a 531 Graham Weigh, both kitted out very similarly in late nineties / early noughties equipment and, crucially, similar quality tyres. One of the rides was over a 50ish mile gently undulating route that I was very familiar with. Subjectively, I would have said I was slightly faster on the Principia ... but in fact it was the other way round! To be fair, the difference was so small it could easily have been down to "noise". So could I tell the difference between the two? Yes. Did it make any difference to my speed? No.

I have since done other comparisons and found similar results. In the last couple of years I have been riding a mid 1960s Woodrup, kitted out with late nineties Campag, mudguards and Continental GP4000 in 28mm (very generous 28mm!) Again, I can find no consistent discernable average speed difference (over 25 - 40 mile routes) between it and my Principia - though both bikes have a very different feel.

Finally, I have ridden my LHT over most of the same routes. It has a triple chainset, wide ratio gears, dynamo lighting and 40mm Voyager Hypers. I am consistently around 1mph slower than on the other bikes. This would be a disaster in any competitive situation, but for most other riding I would suggest it is neither here nor there!

None of this surprises me very much. Once approaching 20mph, and assuming the same rider input, aerodynamics is the main determinant of speed followed by tyre rolling resistance, with weight and other frame related matters being way behind.
by robc02
11 Jul 2021, 9:51pm
Forum: Bikes & Bits – Technical section
Topic: exal LX17 rims
Replies: 8
Views: 462

Re: exal LX17 rims

Mine are a few years old but the eyelets are visibly offset and fairly consistently so.

It is often said that you shouldn't trust manufacturers' quoted ERDs but should measure the actual rims yourself. When I bought mine I asked Spa Cycles to supply hubs, rims and spokes as a package and it all worked OK, so they must have had a reliable ERD at the time.

These are at the budget end of the price range and you usually get what you pay for. One of mine had a varying width (by approx. 0.25mm), causing uneven braking performance.
by robc02
9 Jul 2021, 7:43pm
Forum: Bikes & Bits – Technical section
Topic: Mavic Open Elite as a replacement for Open Pro rims?
Replies: 15
Views: 624

Re: Mavic Open Elite as a replacement for Open Pro rims?

There are (or were) various Ambrosio branded rims with the same or similar profile and ERD to Mavic Open Pro. E.g. Ambrosio Excellence
by robc02
29 Jun 2021, 10:25am
Forum: Bikes & Bits – Technical section
Topic: 1" Road Stem
Replies: 13
Views: 749

Re: 1" Road Stem

ITM Eclypse were available in both quill and 1" threadless:

https://sscycleworks.com/components/ste ... lypse.html
Image

They turn up fairly regularly on ebay (though the days of winning them for 99p seem to be over!)
by robc02
22 Jun 2021, 11:51am
Forum: Bikes & Bits – Technical section
Topic: STI Levers v Bar-end shifters
Replies: 53
Views: 2415

Re: STI Levers v Bar-end shifters

Chris Jeggo wrote: 22 Jun 2021, 11:40am I think of STI levers as more convenient rather than more comfortable.
Yes.
by robc02
22 Jun 2021, 11:50am
Forum: Bikes & Bits – Technical section
Topic: STI Levers v Bar-end shifters
Replies: 53
Views: 2415

Re: STI Levers v Bar-end shifters

I think STIs (and their Campagnolo and SRAM equivalents) are generally pretty reliable. It is true that they are harder to fix than bar end or down tube shifters but if they are unlikely to fail then maybe that isn't so important. In the UK you should be able to get replacements without too much trouble. Whether you are prepared to accept the potential inconvenience and cost is another matter, but I would suggest the risk is low.

Perhaps the most likely problem you might face on tour is a knock that affects the derailleur alignment - but this will be equally fiddly to adjust with any indexed shifter. I am presuming the bar end shifters on offer are indexed, though some have a friction option as well.

As regards comfort, it is purely a personal thing. I have bikes with both systems and swap between them quite happily and find them both equally comfortable!
by robc02
21 Jun 2021, 4:00pm
Forum: Bikes & Bits – Technical section
Topic: UN 300 vs UN XX sealed BB units
Replies: 29
Views: 1843

Re: UN 300 vs UN XX sealed BB units

I've had acceptable service (approx six years of hard commuting and general riding) from Token units BUT I did remove the inner seals and part fill the sleeve with semi fluid grease before using. Others have reported very short life but presumably fitted them as they came.

I needed Campag compatibility so there was little other choice.
by robc02
20 Jun 2021, 7:51pm
Forum: Bikes & Bits – Technical section
Topic: Crank length
Replies: 43
Views: 2360

Re: Crank length

It does seem intuitive that longer legged riders would probably be better suited to slightly longer cranks and vice versa for shorter legged riders. However, over the years there have been various attempts to study and quantify this and as far as I know they haven't been conclusive. It seems most riders can adapt to quite different crank lengths - as far as power production is concerned anyway.

Variations in leverage and foot speed due to crank length must be considered along with gear ratio as in practice all these things combine.

I suppose personal preference and factors such as limited mobility are the main drivers for most people.

Despite all of this I can't help feeling that 175mm cranks are "right" for me and am reluctant to use anything else. All in the mind? - Maybe.

(Just a thought.... my Humber roadster has 165mm (well 6 1/2 inches actually) cranks and it feels fine! But then it gets ridden in a very much more relaxed style than any of my other bikes).
by robc02
11 Jun 2021, 10:15am
Forum: Bikes & Bits – Technical section
Topic: Hub dynamo with capacitor in light
Replies: 25
Views: 1288

Re: Hub dynamo with capacitor in light

Very clever! I wonder what rate of deceleration is needed to trigger it. Would it, for instance be triggered when being slowed down at the foot of a steep hill? I suppose that might not be a bad thing though.

I don't suppose most other road users would recognise it as a brake light but it might serve to draw a bit of extra attention which could be beneficial.
by robc02
10 Jun 2021, 8:07pm
Forum: Bikes & Bits – Technical section
Topic: Hub dynamo with capacitor in light
Replies: 25
Views: 1288

Re: Hub dynamo with capacitor in light

As far as I know, most rear lights for use with generators have their own standlight capacitor. Supernova are an exception. their rear light is fed dc from the front light rectifier / standlight circuitry.

I have had a number of standlights that have progressively failed. In each case the standby period has become gradually shorter until it is non-existant. This is almost certainly due to the capacitor failing. One of them was replaced under warranty, the others I have ignored either because the light was mechanically damaged / cracked so it was due for replacement, or it got so little use it was hardly worth the bother.

Electrolytic capacitors are known to suffer in this way, especially if left unused for extended periods. I have had a couple of "broken down" electrical items (unrelated to bikes) that have been completely rejuventaed by replacing all of the electrolytic capacitors.

As mentioned by another poster, simply re-using the device can sometimes restore some of the function, but the real answer is to replace the capacitor. Unfortunately they are normally surface mounted so are not that easy to replace, but it can be done with a bit of patience. In an ideal world, these would be user serviceable items, but there is little chance of that when a lot of manufacturers don't even think you should be able to change a battery yourself!
by robc02
7 Jun 2021, 12:56pm
Forum: Bikes & Bits – Technical section
Topic: 1957 Raleigh Superbe Restoration Thread
Replies: 150
Views: 9377

Re: 1957 Raleigh Superbe Restoration Thread

Yes, I have seen it but still find it interesting. Thanks.

I did the lining on my family's roadsters using a Beugler lining tool - basically a wheel whose edge is covered in paint from a reservoir. You run the wetted wheel along the path you want to paint. Much easier than the brush method used in the past but still quite tricky.
by robc02
7 Jun 2021, 9:01am
Forum: Bikes & Bits – Technical section
Topic: 1957 Raleigh Superbe Restoration Thread
Replies: 150
Views: 9377

Re: 1957 Raleigh Superbe Restoration Thread

Krashper wrote: 6 Jun 2021, 10:23pm No, I won't be lining the frame. I thought about some stripes, like thin red ones but I've decided against it because it seems more fitting for vintage touring or racing bikes. These bikes weren't state of the art machines so I want to keep it looking humble.
Looking at Raleigh and Humber catalogues from the 1930's and 1950's, they do show lining on various roadster models, and I have seen it "in the flesh" on Raleigh roadsters from the 1960's. I suspect it was dropped on later models - I bought a 1970's / 80's model for someone a few years ago and don't recall it being lined.
by robc02
18 May 2021, 9:39am
Forum: Bikes & Bits – Technical section
Topic: Silca Rises from the Dead
Replies: 33
Views: 2331

Re: Silca Rises from the Dead

Good stuff. I'm a great believer in keeping things going with a few repairs or replacement parts.

Mine has had a new washer and replacement chuck (I still have the original plus some seals as well). I always preferred the wooden handle versions but put up with the plastic one as a robust, if less comfortable, alternative. You might have inspired me to do something about it!