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Roberts redux - John C. Kirk

Nov. 6th, 2011

11:50 pm - Roberts redux

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As I mentioned a few days ago, I'm planning to replace my touring bike, so I went back to Roberts Cycles yesterday. They were sorry to hear about someone stealing the old one, and they'll keep an eye out for it in case the thief (or someone who buys it second-hand) brings it in for repair. However, apparently it's quite common for thieves to just cut through the frame with a hacksaw, strip off the components (e.g. the wheels) and then dump the frame into a river. That's because the frame can be identified by its number, whereas there's no way to trace the components. Basically, it's butchery, and it's even more depressing than the thought of someone else using a custom frame that doesn't fit them.

I spoke to Chas Roberts, and we discussed the various options that were available. I was able to hold up my end of the conversation a bit better than I did last year, which made me feel more confident. He also remembered me from last year, which impressed me.

I said that I specifically wanted a side kickstand this time, rather than a central fork. He asked why, and I explained my problem with the front wheel swinging around. He said that they normally recommend central fork stands because it makes the bike more stable; if you knock against the side stand by mistake then the whole bike will go over. However, I've never had a problem with that on a CRU bike, so he'll fit a side stand for me.

I asked about the handlebar tape. Apparently this isn't stuck to the cork, it's just fixed at the end, so if that comes loose then the tape will gradually unravel (as I discovered). There's no real way around that, but if it happens again then I can try to reattach the end. Maybe I can use micropore or something as a temporary fix.

Regarding racks, he was glad to hear that I'd used the bike for its intended purpose (carrying front and rear panniers); that justifies me getting a tourer rather than an audax bike. (Digressing, I think a lot of mountain bikes are the cycling equivalent of Chelsea Tractors, i.e. they're only ever used on roads/pavements.) I mentioned my problems with the "low rider" racks at the front, and he's going to look at alternatives. However, he also suggested that I could get Ortlieb racks as an alternative to Carradice; since the bags and racks would then both be German, they might fit better together. My front panniers were on the bike when it was stolen, so I need to replace them anyway, and that's an option to consider.

I also asked about carrying my D-lock, and he said that even if there was space for it in the middle, the brackets tend to mess up the paintwork. So, the new plan is to get a Tubus Cargo as my rear rack this time around. That way, I can use velcro straps to put the D-lock on top of the rack if I'm not using panniers. It's a bit wider than the Tubus Logo and there's a small incline at the front to stop things sliding forward into the seatpost. I'm not certain whether the Tubus Locc is compatible with every type of D-lock (since they vary in size), so this will avoid that problem.

Speaking of the seatpost, I mentioned my problem with the Brompton seatpost snapping in half; I'm keen to avoid the same thing happening again! I never had any problems with the seatpost on the touring bike, but it was made out of aluminium, so I wondered whether I'd be better off with steel. The previous spec said "U.S.E." (Ultimate Sports Engineering), and they do two models of rigid seatposts: the Alien (which I had) and the Sumo (a bit tougher). The company use various materials (aluminium, carbon, and titanium), but Chas Roberts said that aluminium would be fine. However, he then went into the back of the shop and brought back a Thomson seatpost, which is normally used for mountain bikes. It's still aluminium, but each post is made from a single "ingot" which makes it stronger. The post is circular on the outside but oval on the inside, i.e. the metal is thicker on the front/back than on the sides: the theory is that this will give extra strength where it's needed while still saving weight. I have to say, I was very impressed by the presentation, since it came in a cloth bag. He didn't actually say "Here's something special, for the discerning customer" but that was the impression I got, and this is the one I'm going with.

This seatpost will be much shorter than the one on my Brompton (since the frame is higher), so it won't have the same amount of torque. (Going back to my Physics classes, moment = force x distance, i.e. the shorter the distance the less overall force is being exerted on the joint/pivot.) I'm not sure whether he showed me the Elite or the Masterpiece, but he'll post me a full spec sheet to review and I'll check it then. I'll need the Elite: this is a bit stronger but also a bit heavier. They're both available in black and silver; the one I saw in the shop was silver, and I think that looks a lot better.

The blurb for the Elite says: "The Thomson seatpost has a clamp, head, and upper tube strong enough to withstand 350 foot-lbs of torque. The tube will start to yield and bend at the seat tube clamp at about 250 foot-lbs of torque. Under severe impact the Thomson seatpost will bend slightly and allow the rider to come to a safe stop or finish the ride." The FAQ says that practically speaking, there's no weight limit.

The corresponding blurb for the Masterpiece says: "The Thomson Masterpiece seatpost has a clamp, head, and upper tube strong enough to withstand 325 foot-lbs of torque. The tube will start to yield and bend at the seat tube clamp at about 230 foot-lbs of torque. Under severe impact the Thomson Masterpiece seatpost will bend slightly but allow the rider to come to a stop or continue the ride." The FAQ then says that the weight limit is 91 kg.

230 foot-lbs = 311.8 Nm (Newton metres), which is 31.8 kg at 1m or 106 kg at 30 cm.
250 foot-lbs = 339 Nm, which is 34.6 kg at 1m or 115 kg at 30 cm.
I'm not sure how much of the seatpost was sticking out of the frame before, but I'm sure it wasn't any longer than that. (I currently weigh about 97 kg.) If you're smaller (lighter) than me then this probably isn't something you need to worry about, but I'm now paying much closer attention to the specs. USE don't offer any similar information on their website, and good luck getting any reliable information if you buy a bike at Asda. The only snag about the Thomson seatposts is that apparently I should "remove clean and re-install every 90 days". That's a nuisance, but I can handle it.

My main concern was gears, so I'm going to get a triple chainset this time. I described my "ratchet pedalling", and he said that aside from knee pain it's going to put a strain on the bike as well. If I'd been stronger, I'd have been putting even more force on it, so this could have created other problems. I snapped a chain on a CRU bike last year (on my way to the London-Brighton bike ride) when I was moving off from a traffic light, and the guy in charge said that I should have been in a lower gear. Based on that, if I'm trying to go uphill in too high a gear (even if it's the lowest gear available) then the same thing might happen, which would be annoying. I was determined to ride up every hill because I didn't want to "cheat". However, pushing a loaded bike uphill can be even harder than riding it.

The only triple chainsets I could see at Wiggle were 50-39-30, but Chas recommended a 48-36-26. That sounds good to me, since it will give me an even easier first gear; the trade-off is that I won't be able to go quite as fast in top gear, but I only used that when I was going down steep hills so it's not really a problem. This also demonstrates the benefit of going to a shop like this: the online retailers only stock the most commonly used components, whereas Roberts can offer a wider selection. I mentioned Josie Dew's gears, and he immediately knew who I was talking about; she rides a Roberts bike, so they have a couple of pictures of her on their wall, and some of her books on display at the counter. However, he said that going down as low as 20 teeth creates new problems because the derailleur collides with the down tube (part of the bike frame), so you need a different type of bottom bracket to get it clear. Basically, you need to consider the overall bike geometry, rather than looking at each component in isolation. Again, this shows the benefit of going to them: while I have my own ideas about what I want, I can also benefit from their expertise.

We discussed the rear cassette, and I'm going to stick with the same one as before (11-32). If I'm in the lowest gear (26 teeth at the front and 32 teeth at the rear), that will give me a gear ratio lower than 1, i.e. the rear wheel will turn more slowly than the pedals. (Since both wheels are the same size, the front wheel will also turn more slowly, but gear ratios just look at the bits that are directly attached to the chain.) I wasn't sure whether a triple chainset would require a 10-speed cassette, but Chas was quite emphatic that this would be a bad idea! The problem is that if you squeeze more sprockets into the same amount of space then the chain has to be thinner, otherwise it would jam. I think that this then makes it weaker.

I forgot to mention lights while I was there, but I've emailed them to request an Axa Nano Plus LED light: this includes a USB socket, so I can use the hub dynamo to charge up gadgets while I'm on the move, e.g. my mobile phone or ebook reader. This would be particularly useful for my helmet camera: if I record for 3 hours, it takes 3 hours to recharge the battery, so I need equal time on and off the bike. I don't mind plugging things into a wall socket overnight, but I don't want to wake up every 3 hours in the middle of the night to swap batteries, or to carry multiple chargers around with me. (I've emailed Contour to suggest a multi-battery charger, and they said that they'd add me to the list of people who've requested that!) I'm not keen on using a satnav while cycling, but a USB charger would also be useful there. I considered a SpyLamp for the rear light (as reviewed by The Guardian), but the website that sells them says "out of stock", so I'll stick with a normal rear light for now.

I want to get a bell fitted as well, but that's an aftermarket issue. It's not really necessary on the road, since I can just shout at "lemmings" (pedestrians who step out without looking). However, if you want to cycle on a canal path then you need a permit from British Waterways. It's free, and you just have to print/sign it, but the code of conduct says "ring with Two Tings", i.e. you need to have a bell. I have to admit that I didn't do this during my LEJOG attempt, mainly because I didn't get round to it before I left, but I heard other cyclists doing it and I want to be more law-abiding. The main challenge is working out where to put it, particularly when I have a bar bag mounted on the handlebars.

One of my CRU colleagues described Roberts as "the Rolls Royce of bikes", and I like that description. They're not the most expensive or flashy; racing bikes are the equivalent of sports cars, where you can spend over £2000 on just the wheels. However, they're good quality, and built to last. It will take a while to make my new bike, particularly since things slow down around Christmas, so I probably won't get it until late January, but that's ok; I normally take a short break from cycling when the roads get icy.

As for the Brompton, I phoned Evans yesterday but they don't have replacement seatposts in stock. They said "You'd have to order that from the warehouse because we're closing". This was at 11:00, so I assume he didn't mean "closing for the day"; are they closing the shop and leaving the area? I also phoned Bigfoot Bikes (where I bought the bike), but they didn't answer the phone. So, I'll order a replacement online, and hoof it for a few days.

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Comments:

From:(Anonymous)
Date:March 11th, 2012 02:39 am (UTC)

Center stand

(Link)
John, check out a steering stabilizer spring to keep your front wheel from flopping over. I've had great success with the Deflopilator from Yuba Bikes:
http://yubaride.com/utility-bikes-accessories
(Reply) (Thread)