January 27, 2020 at 12:47 am #27068VanessaParticipant
*Disclaimer, I am an Automotive Braking Engineer by trade, do not attempt this modification unless you are a competent mechanic with brake system experience because modifying the braking system can cause loss of braking and risk to yourself and others while riding in case anything should go wrong. The below is not a specific guide or recommendation, I am not advocating that anyone else should do this to their bike!
Even though the stock brake lever on my SP401 has an adjustable reach function, I found that it was still a bit too far away from the bars for my small hands/fingers to comfortably grab. I’ve bought those cheap/common aftermarket levers from eBay and suchlike before and found them to be a bit trashy and loose for my liking so I decided to modify the stock lever.
As is usual for me I bought a spare lever in case I messed it up, and also so I could keep riding while experimenting with the lever. The lever has an adjustment dial with 5 settings, with No. 5 bringing the lever closest to the bar. It’s this adjustment mechanism that I needed to modify, but unfortunately the end of the adjuster is peened over (rivetted) in place. Looking at the underside of the lever it’s the rivet-head closest to the outer end of the lever that I drilled out. Apologies that I don’t have many decent photos of this (I forgot to take them) but I only have pics of the end result on the bike.
On the above pic you can see the modification. The screw in the centre of the pic is not normally there, it’s usually the rivetted end of the adjuster dial. Basically I carefully drilled away the rivetted head until I could punch the adjuster dial out of the lever. I was careful to keep the washer as I’d need it later and also noted that there is a spring washer under the dial head itself which must not be lost and which must go back in exactly the same orientation to make sure the adjuster dial ‘clicks’ between settings. Once I had removed the adjuster dial I carefully drilled down into the stem right where I was drilling to remove the rivet head, making a blind hole about 8mm deep. Then I tapped the hole with a suitable thread size. Again I apologise as I can’t remember what thread size I used, it might have been M3 but it needs to be small enough to not weaken the integrity of the adjuster stem. I tapped right to the end of the hole to allow maximum screw thread engagement as I didn’t want the screw to fall out while riding!!! I ground down a plug tap to achieve this.
Now looking at the dial itself there are 5 numbers and 5 corresponding sides to the adjuster pin. Each side is a different distance from the centre of the pin, and so each will hold the lever at a different distance from the bar depending on which is selected. Kind of like a crude 5-sided pentagonal cam. I located the side which was opposite the number ‘5’ as it’s this one I wanted to modify. I carefully filed this surface down by 1mm depth. I didn’t go any further as I didn’t want to overly weaken the shaft of the adjuster dial (the pin). This will allow the lever to sit closer to the bars when set at position 5, the other 4 positions were untouched and thus remain the same as stock.
Then I re-assembled the lever and used a suitable countersunk screw (see above pic) to hold the adjuster dial in place. The head of the screw needs to be larger than the hole in the washer. The screw length needs to be just slightly less then the total depth of the hole drilled in the adjuster shaft so when tightened up it doesn’t bottom out and hence stay loose. I used Loctite retaining compound on the screw thread to keep it in place, VERY IMPORTANT. Then I put the lever back on the bike and set the dial to position 5. It worked like a charm! The lever is now close enough to the bar for me to reach easily, but not too close that it would hit the bar while braking (VERY BAD) as this would prevent full braking power during an emergency stop. Like I said, this mod should only be attempted by an experienced mechanic or braking engineer. See the pic below which shows me pulling the brake lever in:
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