Disc Brake on my Bike Friday

Today I visited Bike Friday dealer ehicle in Shinjuku, Tokyo to have a disc brake installed on the new fork that Bike Friday has made for my 4 year old bike. I had bought the Shimano BR-CX77 calliper second-hand from a friend. This conversion will make for much more consistent braking on rainy brevets or on wet shopping rides.

There was one small issue but it was quickly solved by ehicle. My friend had also given me a SM-MA-F160P/S adapter for fitting a post mount calliper like the BR-CX77 to an IS tab front fork with a 160 mm rotor. That’s exactly what I had on the Bike Friday. However, it did not fit together, the calliper sat too far out from the adapter. Comparing with the setup of a disc-equipped Bike Friday Silk in the shop we found that its Avid BB7 calliper was mated to a Shimano SM-MA-F180P/S, which is meant for a 180 mm rotor at the front or 160 mm at the rear (F180P/S = R160P/S). The adapter I got from my friend was for use with a 160 mm rotor at the front or 140 mm at the rear (F160P/S = R140P/S).

The use of a 160 mm rotor with an F180 adapter (i.e. R160) on the Silk fork suggests that the IS tab to axle distance on the BF fork is the same as on a standard rear setup. This means it takes a 180 mm front adapter for a 160 mm rotor or a 160 mm front adapter for a 140 mm rotor. This is very interesting, since Shimano doesn’t make 140 mm front P/S adapters: Using Shimano parts, you can’t normally use a 140 mm rotor at the front with an IS tab fork, but with Bike Friday’s setup you can because the spacing is like at the rear, where Shimano does support 140 mm rotors with IS tabs. The only thing you give up by using rear spacing at the front is the ability to use 203 mm rotors, but the fork doesn’t have enough clearance for those anyway and they’re not needed on a 20″ wheel bike. The smaller wheel means that a smaller rotor can match or beat a bigger rotor on a 700C wheel on stopping power, though heat dissipation for long descents still depends on rotor size.

Anyway, a cheap 180 mm Shimano adapter instead of the 160 mm one that I had brought along solved the issue and I could use the new brake with the 160 mm rotor on the new fork. The B&M dynamo headlight moved from the brake bolt in the fork crown to its own bolt in the same place. ehicle installed a longer brake cable for me to accommodate the different brake location.

I love the new brake, both its stopping power and modulation. It should make a huge difference on rainy rides, where I have always been uncomfortable with rim brakes, in particular on brevets where I don’t know what the weather will be like on the day when I sign up for an event. I’ve done one 300 km brevet where it was raining for 150 km.

I’d like to thank ehicle for their friendly and efficient service and recommend them to anyone interested in or already riding a Bike Friday 🙂

The last brevet of the season

BRM926 AJ NishiTokyo 200 km Kintaro on September 26 was the last brevet of the year for me, even though the Japanese Randonneuring season runs until October: I won’t able to attend AJ NishiTokyo’s West Izu brevet on October 17 due to business travel.

I had not prepared particularly well for BRM926. After a heat wave in early August we had lots of rain, then one of my brothers visited from Germany, then I traveled to the US again. I did not really get to do as much cycling as usual. So far I had not experienced any DNF (Did Not Finish) on any of my 200 km brevets, but I was a bit worried that this could be the first time on this very hilly course.

I got up at 03:45. In the front car of the first train heading out to Machida I met two other participants. In front of the station I unpacked the bike in the rain and rode out to the start (5 km) with one of the other guys. On the way the rain stopped and I took off and packed away my rain gear before the ride briefing. A week before the event, the weather forecast had predicted rain, but as the week progressed it gradually improved.

The day started off cool and never got too hot, but mostly staid dry. Around higher elevations, especially after going over a pass or through a tunnel through a mountain range we encountered slight drizzle again (really, we were just riding through clouds). The strongest was crossing from the Yamanakako side of Kagosaka Toge to the Gotemba side. But the drizzle always stopped when elevation dropped and we got out of the clouds again.

The course had three convenience store check points (point de contrôle, PC) roughly 60 km apart, as well as one quiz point and one manned but untimed check point. It headed from Machida via route 35/Akiyama to Tsuru and from there up to Kawaguchiko. After circling the lake it headed past Yamanako, over to the Ashigara mountains to a barbecue site called Yuhi no Taki (evening light waterfall) and back to Machida.

After the Akiyama road with the first big climb near the Maglev track I reached PC1 at Tsuru with only about 15 minutes spare before control closing time. That set the tone for the day.

I was continually chasing the next closing time, thinking I’d probably make it but could never be too sure until I reached it. At the top of a mountain I would always find myself behind the minimum average speed of 15 km/h from the start, but on the next descent I’d gain just enough distance in a short time that I was a little bit ahead of the minimum at the next PC again. Most of the time I cycled alone, but I came across the same three or four cyclists again and again.

At Lake Kawaguchiko I couldn’t see Mt Fuji because it was too cloudy. Given the forecast, I hadn’t expected to see it.

The highest point was Kagosaka Toge, about 1100 m. From there the road dropped over 700 m, which is a pretty long descent. PC2 at the bottom was a grocery store, where I arrived just 12 minutes before control closing time. I bought bananas and climbed up Ashigara Toge (6 km).

On the other side I descended 6 km, then climbed a valley to a barbecue place which was a manned checkpoint (untimed). Staff had prepared grilled seafood and meat. They had saved some Frankfurter sausage and chicken for me, which I ate only 13 minutes before they had to clear out of the place. Then I descended to Oi-Matsuda and across a mix of rolling hills and busy urban roads back to Machida.

PC3 felt like the biggest challenge as traffic and traffic lights got denser, with the hills still unrelenting. I arrived at PC3 with 14 minutes spare. Two other cyclists arrived 3 and 5 minutes later, as I was preparing to head off again. Due to the overall 200 km time limit being 10 minutes longer than the 15 km/h equivalent time limit of all intermediate controls, I gained more breathing space at the final PC and could take it relatively easy for the remaining 26 km, which had yet more hills and traffic. It was then that I could stop worrying about time. I arrived at the goal 20 minutes before control closing time, with the other two guys following soon.

From there it was an untimed 5 km back to the reception site, the Cherubim bike shop in Machida. Three cyclists behind me also completed. Quite a few others DNF’ed (dropped out) due to various problems, including mechanical problems (a broken front derailleur, a ripped off rear derailleur after a crash, etc). We relaxed, celebrated and talked.

After the AJ NishiTokyo staff tidied up we took a group picture. I then cycled home from Cherubim to Setagaya. I got back at 23:30 with 242 km recorded on Strava and close to 2900 m of climbing, including the return ride.

The next day I felt a bit sore, but not too bad. The adrenaline of an event lets you do amazing things. My brevet speeds are always significantly higher than my personal ride times because there is always a ticking clock and/or other riders to chase. Knowing I can achieve goals in brevets that I don’t normally achieve on my own encourages me to become more ambitious and aim higher.