Modifying Ergon Grip (GP1-L Biokork) for Brompton - Step by Step with Photos
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Modifying Ergon Grip (GP1-L Biokork) for Brompton - Step by Step with Photos
If it helps anybody, here are step-by-step photos of removing the foam grips from my Brompton and replacing them with the Ergon GP1-L Biokork grips. Total time about 45 minutes if you're fussy.
Note: Check that the clearance of the handles on either side (distance brake and/or shifter attachments re the same distance from the bar ends). I found my left ones to be 10 mm different from the right side, meaning I would have ended up with two differently measured and cut Ergon grips if I wasn't paying attention, unless that's what you want, of course...
I debated removing the foam grips in one piece based on another blogger's write up that wanted to keep the grips, but I decided it wasn't worth my time. I used a utility knife and cut at an angle through them. I didn't cut knife point down to avoid scratching the handle itself. I did keep the cut grips though figuring it might be useful for padding.

After cutting, you can "peel off" most of the grip and slip it off, except for wherever the glue is. Note to Brompton: such a nice bike, and you glue foam handles on? Seriously?

To remove the residual glue/foam bits, I didn't want to scratch the surface, but obviously just using my hands to scrape the residue wasn't going to work. I found a used nylon dish scrub pad with some lens cleaner (dish detergent or rubbing alcohol would probably work well too) worked well. You may have some glue gunked into the hollow bar ends - more about this later.

You obviously want the new grip to be fully inserted on the bar, which means you need 130 mm of clearance according to Ergon's instructions. I found that my Brompton only offered 102 mm of clearance from bar end to shifter/brake attachment. I felt that if I had cut the Ergon grips to 102 mm length, I would not have enough hand surface remaining to comfortably and securely hold the grip. I noticed the inner plastic sleeve of the Ergon grip is in two pieces: about 2/3 of the length is towards the narrow end, and 1/3 of the end is towards the wider, locking end. I think only the outer 1/3 portion that tightens around the bar as the locking bolt is tightened. If so, I figured if I extended my grips a bit to about 112 mm to 114 mm total length to give me more hand surface, enough of the outer sleeve will still lock around the bar, and the force of the bolt itself is still reasonably inline with the handle to not fracture the locking sleeve under compression. Yes, I realize this might not be the safest, but I figured it was the best tradeoff. I can also still cut more off in the future if necessary. Note: I can see the extra length being an issue if you have and want to use stems on the grip: probably would create too much unsupported moment.

I used a hacksaw to cut because I wanted to avoid a jagged edge as much as possible. Since the grips are irregularly shaped, I used a vice to hold them.

The cut came out pretty clean! Some sandpaper took off any rough edges. Hint: use your finger to support the end being cut to prevent too much movement and cut with less force towards the end to avoid breaking the material as it weakens with each successive cut.

Here is one grip mounted. Looks sharp!

This is what I meant by available hand surface. Even when cut to about 113 mm, I don't have much left to grasp onto. 102 mm would have been tough to hold securely for me, and I don't have particularly large hands.

As a double check before I pounded in the grip plugs, I wanted to make sure the grips cleared the floor since I left a bit extra length. (They do!)

Here's the odd thing about the grip plugs. I wasn't able to get all the glue out of the hollow bar ends, and so they impeded getting the plugs in without significant pounding (rubber mallet). However, they would act somewhat as compression supports when tightening the locking bolts, so I wasn't overly concerned about damaging the grips (don't overtighten obviously).
All done! They feel great too when riding.

That's it! Next mod.. maybe some roller wheels for the rack. Hope this was helpful to those interested in installing the Ergon grips.
Note: Check that the clearance of the handles on either side (distance brake and/or shifter attachments re the same distance from the bar ends). I found my left ones to be 10 mm different from the right side, meaning I would have ended up with two differently measured and cut Ergon grips if I wasn't paying attention, unless that's what you want, of course...
I debated removing the foam grips in one piece based on another blogger's write up that wanted to keep the grips, but I decided it wasn't worth my time. I used a utility knife and cut at an angle through them. I didn't cut knife point down to avoid scratching the handle itself. I did keep the cut grips though figuring it might be useful for padding.
After cutting, you can "peel off" most of the grip and slip it off, except for wherever the glue is. Note to Brompton: such a nice bike, and you glue foam handles on? Seriously?

To remove the residual glue/foam bits, I didn't want to scratch the surface, but obviously just using my hands to scrape the residue wasn't going to work. I found a used nylon dish scrub pad with some lens cleaner (dish detergent or rubbing alcohol would probably work well too) worked well. You may have some glue gunked into the hollow bar ends - more about this later.
You obviously want the new grip to be fully inserted on the bar, which means you need 130 mm of clearance according to Ergon's instructions. I found that my Brompton only offered 102 mm of clearance from bar end to shifter/brake attachment. I felt that if I had cut the Ergon grips to 102 mm length, I would not have enough hand surface remaining to comfortably and securely hold the grip. I noticed the inner plastic sleeve of the Ergon grip is in two pieces: about 2/3 of the length is towards the narrow end, and 1/3 of the end is towards the wider, locking end. I think only the outer 1/3 portion that tightens around the bar as the locking bolt is tightened. If so, I figured if I extended my grips a bit to about 112 mm to 114 mm total length to give me more hand surface, enough of the outer sleeve will still lock around the bar, and the force of the bolt itself is still reasonably inline with the handle to not fracture the locking sleeve under compression. Yes, I realize this might not be the safest, but I figured it was the best tradeoff. I can also still cut more off in the future if necessary. Note: I can see the extra length being an issue if you have and want to use stems on the grip: probably would create too much unsupported moment.
I used a hacksaw to cut because I wanted to avoid a jagged edge as much as possible. Since the grips are irregularly shaped, I used a vice to hold them.
The cut came out pretty clean! Some sandpaper took off any rough edges. Hint: use your finger to support the end being cut to prevent too much movement and cut with less force towards the end to avoid breaking the material as it weakens with each successive cut.
Here is one grip mounted. Looks sharp!
This is what I meant by available hand surface. Even when cut to about 113 mm, I don't have much left to grasp onto. 102 mm would have been tough to hold securely for me, and I don't have particularly large hands.
As a double check before I pounded in the grip plugs, I wanted to make sure the grips cleared the floor since I left a bit extra length. (They do!)
Here's the odd thing about the grip plugs. I wasn't able to get all the glue out of the hollow bar ends, and so they impeded getting the plugs in without significant pounding (rubber mallet). However, they would act somewhat as compression supports when tightening the locking bolts, so I wasn't overly concerned about damaging the grips (don't overtighten obviously).
All done! They feel great too when riding.
That's it! Next mod.. maybe some roller wheels for the rack. Hope this was helpful to those interested in installing the Ergon grips.

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Awesome write up, Ozonation! That saves me from doing a step by step writeup that I was going to start tonight!
I will post some info on my experience though since I bought the grip shift version where no cutting is needed. BTW, my hand is the perfect "width" to rest fully on the grip shift version....actually looks like the same hand surface clearance as your hand on your newly cut grip.
I'm excited to start installing mine tonight! Yours look really nice installed! Nice job!

I'm excited to start installing mine tonight! Yours look really nice installed! Nice job!
#3
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Good for you! I couldn't find the grip shift versions.
What the heck..

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Sadly, if you were in the States, there are plenty of retailers who have the grip shift versions and do free shipping. I just checked the ebay store where I got my grip shift versions from and it's free shipping in the US, but $15 shipping to Canada.
Although, now that I just did the math, it would still be a tad cheaper if did you pay that shipping. $28 grips + $15 shipping = $43...I saw an etailer in Canada where they had them for $49.

#5
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True... I was surprised to see that my local LBS had them. They've been very helpful, if there was a problem prior to cutting I'm sure I could have returned them, and I bought some lights, so they gave me a 10% discount anyways! It's amazing the difference in terms of choice between Canada and the US.
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For the record, this procedure is for a M/H handlebar. Recent S handlebars to not require to cut the grip.
Also, Ergon provides this extra reinforcement https://www.ergon-bike.com/us/en/product/ls100 to counterbalance the grip clamp force .It fits S handlebars, possibly also M/H.
Also, Ergon provides this extra reinforcement https://www.ergon-bike.com/us/en/product/ls100 to counterbalance the grip clamp force .It fits S handlebars, possibly also M/H.
#7
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S is for straight , largely same as many MTB bars,
so Of course the grip does not have to be cut.
so Of course the grip does not have to be cut.
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The flared side looks like it points up quite a bit...? I thought horizontal would be closer to most comfortable? The hand's outer heel is for resting on the flare.
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Ozonation - Question for you regarding the plugs. Do you recall the sizing of the plug in relation to the diameter of the handlebar tube? My plugs have three "tiers" if you will. The first one is a smaller diameter compared to the other two (they're actually squares, so diameter doesn't quite make sense, but bear with me. A first smaller tier makes sense, because that tier is the first to be put into the handlebar. However the smallest tier is still way too big for the handlebar tube, which means the other two tiers are definitely too big.
I'm talking the smallest tier is about 2mm bigger in diameter than the hole and the other tiers are about 3mm too big. I tried using a mallet and was deforming the tiers, but there is no way those things are going into the handlebar tube.
Do you recall if your plugs were like that?
I wonder if grip shift plugs are different than regular grip plugs.
I'm talking the smallest tier is about 2mm bigger in diameter than the hole and the other tiers are about 3mm too big. I tried using a mallet and was deforming the tiers, but there is no way those things are going into the handlebar tube.
Do you recall if your plugs were like that?
I wonder if grip shift plugs are different than regular grip plugs.
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#11
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Ozonation - Question for you regarding the plugs. Do you recall the sizing of the plug in relation to the diameter of the handlebar tube? My plugs have three "tiers" if you will. The first one is a smaller diameter compared to the other two (they're actually squares, so diameter doesn't quite make sense, but bear with me. A first smaller tier makes sense, because that tier is the first to be put into the handlebar. However the smallest tier is still way too big for the handlebar tube, which means the other two tiers are definitely too big.
I'm talking the smallest tier is about 2mm bigger in diameter than the hole and the other tiers are about 3mm too big. I tried using a mallet and was deforming the tiers, but there is no way those things are going into the handlebar tube.
Do you recall if your plugs were like that?
I wonder if grip shift plugs are different than regular grip plugs.
I'm talking the smallest tier is about 2mm bigger in diameter than the hole and the other tiers are about 3mm too big. I tried using a mallet and was deforming the tiers, but there is no way those things are going into the handlebar tube.
Do you recall if your plugs were like that?
I wonder if grip shift plugs are different than regular grip plugs.
In your case, I'm not sure why Ergon had the plugs designed that way. Maybe other bike bars are a bit wider? I would think that you might have to shave down the tiers a bit.
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I recently put Ergons on a friend's bike. Those end plugs were an unfathomable joke, impossible to install. They didn't used to be like that.
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Okay, good to know it seems like an issue with the plugs. I think I'll hack up my own plug solution. I have a couple ideas already.
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Haha! I did exactly the same thing two weeks ago (it must have been in the air). . I didn't see this post. I am thinking of securing the ends with electrical tape, or alternatively, using some twine (and lacquer) as Rivendell does on their cork grips. . . Thoughts?
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I'll post pictures as soon as I decide on a final finish (BTW, we did pound the end plugs in the bars - using two of us and a rubber mallet).
#16
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GC3. in prior numbering system, bar end + grip are held by 1 bolt.
tempted to go to the shortest one, to fold easily..
but would cover the end of the bar too.
at least the composite ones..
update, yup, without the hook around of the current #GR5,
the GR3 on my M bar Brompton, folds down to the Catch , fine.
tempted to go to the shortest one, to fold easily..
but would cover the end of the bar too.
at least the composite ones..
update, yup, without the hook around of the current #GR5,
the GR3 on my M bar Brompton, folds down to the Catch , fine.
Last edited by fietsbob; 06-19-12 at 02:28 PM.
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I'm going to visit Riv bikes when I'm up in Monterey in two weeks - hopefully I'll decide and post some pictures the next weekend! I'm not adverse to electrical tape (black? tan?) - or twine (the twine I have is very thick, so checking Riv's). Just like you - I cut both my grips I cut shorter and even - didn't think to cut around the gearing. . . . I love them though - highly recommended!!!
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I finally used red twine with clear lacquer, rather than the hemp/cotton twine. I also tried electrical tape and pattern tape - with little good results. I think I would probably recommend the grip shifters - I simply didn't realize they existed at the time of purchase.
https://flic.kr/p/cg4Frw
https://flic.kr/p/cg4F4J
P.S. I could not for the life of me figure out how to post a photo attached to this message -the uploader simply wouldn't work (may be user error).
https://flic.kr/p/cg4Frw
https://flic.kr/p/cg4F4J
P.S. I could not for the life of me figure out how to post a photo attached to this message -the uploader simply wouldn't work (may be user error).
Last edited by pammieellen; 06-17-12 at 07:52 PM. Reason: Working on the links.
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I finally used red twine with clear lacquer, rather than the hemp/cotton twine. I also tried electrical tape and pattern tape - with little good results. I think I would probably recommend the grip shifters - I simply didn't realize they existed at the time of purchase.
https://flic.kr/p/cg4Frw
https://flic.kr/p/cg4F4J
P.S. I could not for the life of me figure out how to post a photo attached to this message -the uploader simply wouldn't work (may be user error).
https://flic.kr/p/cg4Frw
https://flic.kr/p/cg4F4J
P.S. I could not for the life of me figure out how to post a photo attached to this message -the uploader simply wouldn't work (may be user error).
Thanks for this writeup. I'm about to do this as well, as my grips will not fit on my touring handlebars before the bend while still allowing room for the brakes and thumb shifters.

**not my bars, but an example of what I am trying to do.
You state a few times that even at 113 mm your hand barely fits on the grip. The twist shift Ergons are only 95 mm and operate on the premise that part of your hand can rest on the grip shift. In our cases, there is no grip shift, we simply don't have enough space to fit the longer grip. It seems cutting down these longer grips from 130 to 115 mm would be a much better option that using a 95 mm grip in our case (allowing an extra 20 mm), as long as the grip holds up after hacking off then end.
Are they still holding up?
How has the twine and lacquer worked out? I think it looks really sharp and unique, but was there any practical mechanical reasons for doing this? Were you worried that the grips were going to start falling apart at the cut end? Was there a specific kind of lacquer that you used? I'm guessing the lacquer acts as a glue?
Thanks! Good writeup and good work.
Last edited by steltz02; 04-05-13 at 04:22 PM.
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Any experience of fitting these WITH gripshifter on a Brompton?
If it helps anybody, here are step-by-step photos of removing the foam grips from my Brompton and replacing them with the Ergon GP1-L Biokork grips. Total time about 45 minutes if you're fussy.
Note: Check that the clearance of the handles on either side (distance brake and/or shifter attachments re the same distance from the bar ends). I found my left ones to be 10 mm different from the right side, meaning I would have ended up with two differently measured and cut Ergon grips if I wasn't paying attention, unless that's what you want, of course...
Note: Check that the clearance of the handles on either side (distance brake and/or shifter attachments re the same distance from the bar ends). I found my left ones to be 10 mm different from the right side, meaning I would have ended up with two differently measured and cut Ergon grips if I wasn't paying attention, unless that's what you want, of course...
#22
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That's what Im using I just filled in the gap between the end of the ergon grips and the brake lever mounting band
1st with a left over bit of cushion handlebar tape, then I just cut down a short section of a round grip and slid it on the bar
then fitted the Ergon grips back on.
IDK about the S-A 8 speed I stayed with the BSR (+ Mountain drive crank.)
Making a cross bar between the M bar's U uprights of more 7/8" tube ,
could give you more space to mount that grip shifter in the Center.
got any DIY fabricating creativity?
1st with a left over bit of cushion handlebar tape, then I just cut down a short section of a round grip and slid it on the bar
then fitted the Ergon grips back on.
IDK about the S-A 8 speed I stayed with the BSR (+ Mountain drive crank.)
Making a cross bar between the M bar's U uprights of more 7/8" tube ,
could give you more space to mount that grip shifter in the Center.
got any DIY fabricating creativity?
Last edited by fietsbob; 09-10-14 at 02:07 PM.