Installing a fatter tire onto the Brompton

[2019 Update: I had all sorts of issues with the Scorchers on RSVP this year. Long story short: the rear tire wore right through to the casing, and I didn’t notice this before the ride. The little dimples on the tire do not work as wear indicators since they are off the centre line. There is a new higher volume 349 tire by Continental that should be a good alternative.]

2020: Further update: although there was some chatter about early samples of the continental tire being higher volume and thus having some issues with fender clearance, the production version is smaller, and is in fact comparable in volume to the regular Schwalbe Marathon. My notes on the new tire are here.

In about three weeks I’m due to ride Seattle to Portland, just like two years ago. I’m going to do it on a folder again, but this time on the Brompton, rather than the Tikit.

I’ve been a little concerned as I seem to be pretty slow on the Brompton, having difficulty maintaining a 20 kph pace, even on shorter rides. Of course this might been that I’m just not in as good shape as two years ago, but I still have the impression that the Brompton is a bit more sluggish.

This past weekend, I decided to tweak the Brompton in search of a little more speed. Main items on the menu: faster tires and clipless pedals.

I didn’t want to go for the Kojaks as I’ve heard that they are quite flat prone. They are also too skinny for city riding in Toronto; they wouldn’t play well with streetcar tracks or sewer grates.  I decided to move the Greenspeed Scorchers over from the Tikit.

Problem: the Scorchers are a significantly higher volume tire than the stock Marathons.

The front tire went on with no fuss. However the back tire was a different story.

Firstly, I should note that I had already put a titanium rear rack from H&E on the bike, and had to remove two of the stock fender stays in the process. This is what the rear end looked like with the H&E rack, but only one set of fender stays.

As it turns out, to get the stock fender to clear the bigger tire, I had to remove the remaining fender stay. I also had to remove the mounting plate that I used to anchor the rear of the fender.

Once I did all that, the stock fender just barely cleared the fender, and it was rideable, with just a bit of rubbing. That fender clearance is really minimal.

I decided in the interest of reliability that I should try to fit a larger fender: a 16: “Freddy Fender” from Planet Bike. Although the new fender was only minimally wider than stock, the profile of the new fender was more rounded and would fit the Scorcher better…. or so I thought.

However, there was work to do. First item was to modify the brake bridge mount so that the fender could move closer to the brake bridge, just like the stock fender (to the left)

After a little work with the Dremel.

It turns out in the end that I had to pay attention to three points to get adequate clearance. Firstly, the front of the fender had to be trimmed shorter so that it would sit above the frame.

Second, the brake bridge mounting bracket had to be bent to clear the rack mount.

Finally, the mount at the rear of the fender had to be modified. However I was able to use a stock hole on the new fender (after I removed the mudflap).

After reading various comments on the web, I was prepared to have trouble with the removal and reinstallation of the rear wheel. However, it was no problem. Just remember to put the dropout clips in the correct orientation, even when you are working on the bike upside down.

Also use a nice wide set of tire levers. My favourites are Pedros, or the slightly harder to find ones from Schwalbe.

With the new fender in place, I think the fatter tire makes the bike look a little more aggressive.

This is the set up that I rode Sunday night with no issues.

I also installed new clipless pedals, using the MKS EZ superior system so that it would be easy to swap in platform pedals for city riding.

A couple of weeks ago, I also swapped out the M bars for the Joseph Kousac midrise bars (I’ll write this up separately). I also installed some older Cane Creek barends that unfortunately are no longer made.

Also some Sped Dial hinge clamps. Highly recommended.

With the new bars, the stance of the bike is a little more aggressive, with the bars about level with the saddle. This is with the saddle about a finger’s width lower than the highest position for the stock length seat post, which is right height for me.

Also, last nights ride required lighting, so I picked up the Brompton specific Volt 400 light.

It was a breeze to install, and it put out a decent amount of light; you might be able to tell from this picture. That’s my headlight beam in the foreground.

For a taillight, I had picked up the Cateye taillight that clips onto the 2017 and later Brompton saddle.

However, I cannot recommend this light for one reason. Even when I bought it, I noticed that it didn’t seem to click very positively onto the saddle mount. Sure enough, it dropped off during a ride, but I noticed and picked it up. At that point I should have taped it into the mount. However, at some point in the next couple of days, it dropped off again, and so I didn’t have a taillight for Sunday.

I found an alternate solution: the Planet Bike taillight clip has the same mounting bolt spacing as the Brompton rear reflector.

I thought it would be a problem for the bottom tab on the mount to hit the rear tire.

However, this turned out not to be an issue. I bent the mount out enough to clear the tire, and it was still easy to mount and dismount the taillight.

Here you can see that the Planet Bike superflash does not interfere with the fold, at least when you have a rack with EZ wheels.

UPDATE: there is enough flex in the mount on the rack that the plastic tab can get caught in the tire so this is not an ideal solution.

I’ll be doing a few more tweaks before STP, but the main thing now is to train some more….