In order to eliminate this risk, I decided to change the pedals to the removable type, which will allow the pedal to be stowed away when folded. This also makes the folded package even more compact as there is no folded pedal on the left side crankarm.
The most popular and reliable removable pedals are made by MKS, and their quick release (QR) pedals are found on many folding bikes. Before swapping the pedals, let's take a look at the stock Brompton pedals.
Brompton left side folding pedal. A rather nice folding design, although there will be load passing through the plastic body when loaded in one of the directions.
Remaining width when the left side pedal is folded. This picture is misleading, as the pedal body is actually mostly behind the crankarm, with only the bearings exposed on the outside.
Left side pedal folded, with oversized bearings used to take the load.
The right side pedal is not a folding pedal, as there is no need to. When folded, the right pedal will be tucked in beside the front wheel, and does not stick out from the side or back of the folded bike.
Now, for the new MKS QR pedals, I chose the Promenade Ezy pedals as it has a simple design that will match the Brompton.
MKS Promenade Ezy pedals. The Ezy refers to the removable version of the pedals.
All the parts that come with the pair of pedals. There is a nice little pouch to hold the pedals if you need to.
Pedal washers will be needed if you have a recessed area on the crankarm, or if you want to adjust the Q factor of the pedals.
Yellow stoppers that clip onto the QR adapter, to prevent accidental release of the pedals.
Pair of MKS Promenade Ezy pedals weigh 355 grams
Brompton stock right side pedals...
Brompton stock left side folding pedals, very heavy for a pedal.
Stock pair of Brompton pedals, at 411 grams.
Before installing the pedals, I thought of checking the crank arm offset of the new Tiagra crankset, to see if I need to adjust the pedal position by adding pedal washers. The idea is to make sure that both pedals are located equidistant from the centre line of the bike, so that both left and right feet are positioned symmetrically.
To simplify measurements, I just used a vernier caliper to measure the distance from the Brompton main frame to the outside of the crank arm, where the pedal attaches. This method is shown below.
If you want to know the Q factor of the bike, just add up both measurements (left and right side), and minus off the diameter of the main frame.
Right side measurement is about 96.9mm
Left side measurement is about 99mm.
This measurement result is quite strange, as the right side is less than the left side. I had already placed a spacer of 3.6mm on the right side bottom bracket, and yet the right side measurement is less than the left side. I checked multiple times but always got the same result. Could the bottom bracket shell of the frame be offset to one side? Could it be due to the crankarm?
The outer diameter of the main frame is about 45mm. With these info, we can calculate the Q factor of this bike.
Q Factor = 96.9 + 99 - 45 = 150.9mm
This is after adding 3.6mm spacer on the right side of the crankset. The results show that in order to make the pedal position more symmetrical, I should add the pedal spacer on the RIGHT side, since the measurement is lesser than the left side.
Pedal spacer thickness is 1mm each. I shall put just one spacer, even though two will balance out the pedal position perfectly. Q factor is increased to 151.9mm.
Comparing the platform width of the stock right side pedal with the new MKS pedal. Almost the same, except for the missing bridge at the end of the MKS pedal.
For the right side pedal, there is no need for removal at all. The yellow stopper is thus installed on the right side to prevent any accidental removal.
MKS pedal adapter on the left side Tiagra crankarm, after the MKS pedal is removed. As the left side pedal will be removed more frequently, I opted to leave out the yellow stopper.
After folding the Brompton, the left side MKS pedal will be removed from the adapter for compact folding. As there is no yellow stopper on the left side pedal, I just need to take extra care during installation to make sure it is engaged properly with the pedal adapter.
What do you do with the left side pedal after removing it? If you are thinking of carrying it in a bag or somewhere else, there is a risk of leaving the left side pedal behind, separated from the bike. Luckily, there is a solution!
MKS QR pedal holder! Designed to hold onto the loose left pedal after removal.
This pedal holder will be installed on the rear hub axle, on the left side.
The pedal holder is designed to be fixed at a certain angle, ready to receive the pedal.
MKS pedal clipped into the pedal holder
After folding, the pedal holder will hold the left side pedal together with the bike, to prevent the pedal from being left behind somewhere.
With this new pair of MKS pedals, there is no need to fold the left side pedal anymore. Instead, the left side pedal is removed and clipped into the pedal holder.
Although it takes a bit longer to remove the pedal compared to folding the pedal, I prefer this as it eliminates the risk of scratching the frame, while it also makes the folded width a bit smaller. Also, the MKS pedals have a full metal construction for strength, as compared to the stock Brompton pedals which has some plastic parts on it. It is nice to use good quality pedals as compared to the lower quality stock pedals.