Delmeekc Posted February 24, 2020 Posted February 24, 2020 After the previous few topics on the tyre fitment I decided to have a go but taking a different tact as didn't want to cut all the inner shell apart. I'll add photos and what I did once all the photos sync. I also wanted to be able to return it to standard if I don't get on with the tyre. Basically I trimmed the side of the tyre, raised the body 11mm and did a small amount of trimming of the front and back transparent covers that house the LEDs. 2 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 (edited) First job was to see how much I could trim off the side tread without out cutting the side wall. I made a jig out of some wood and used a hot plate from a plastic welding kit lockwired to a Stanley blade which was screwed in place. Edited February 24, 2020 by Delmeekc Added some info to the text 2 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Some more photos of the jig and the plastic welding control. 1 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Fitted in half of the body and you can see there hardly any clearance. And very tight where the tyre comes out of the body. 2 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Side clearance is ok from the body with the shaved tyre. 2 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Instead of cutting the body I decided to raise the body by 11mm. Luckily I had some 13mm billet which is a nightmare to work with by hand but managed it all with one blade. I made a spacer for each side for the top holes and taped new holes in the plates for the bottom holes. All 4 had to be drilled and taped. For the middle holes I'll be cutting some new holes in the body 11mm lower. 2 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Photos, top spacers are also screwed to top of the side plates. 3 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Then modding the body, lowering the middle to fixing holes and enlarging the hole for the axle nut. 2 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Finished mounting the body raised by 11mm. Changed 2 bolts as they had knackered threads. 3 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Body mounted and put together, photos show new clearance. 2 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 Fitting the transparent covers proved a little difficult so had to trim a section out of each, didn't want to cut the whole length as only fouls on the side part of the tyre as it passes. Used a homemade hot wire to cut the plastic, not my best work but doesn't look too bad. 1 Quote
Delmeekc Posted February 24, 2020 Author Posted February 24, 2020 A few more photos, clearance is ok but photos don't really show it. 2 Quote
Popular Post Delmeekc Posted February 24, 2020 Author Popular Post Posted February 24, 2020 So all complete, I tested it after each stage on the stand and there doesn't seem to be any rubbing. Need to go for proper test tomorrow and see what tyre pressure to set and see how it rides. I tried 30, 35, 40 and 45 psi. Only the 45 psi made the tyre slightly wider and taller by 1mm. Build done at 45psi. May also need to seat tyre a little better as it has a slight egg shape when spinning fast but will test it first incase I need to do some further mods. 5 Quote
greentung Posted February 25, 2020 Posted February 25, 2020 This is the most thorough wide tire mod I've seen for the MCM5. Impressive work. 2 Quote
alcatraz Posted February 25, 2020 Posted February 25, 2020 Nice work! For other readers considering this I suggest to try the CST C-1488 tire if you don't want to modify the EUC. Those have a bit thinner tread and 2.5in tires can sometimes fit without modifications to 2.125in eucs. The tire rubs when deflated and then clears the case when inflated. 3 Quote
Delmeekc Posted February 25, 2020 Author Posted February 25, 2020 So been out for a ride and tried a few different pressures. My 2.125 I had to run at 45psi and nothing less. Tried the 2.50 at 45 and 40 psi and was horrible, twitchy and not stable. Then I tried 35psi and after a few minutes I'm wizzy about, did a few miles of my usual play area and much better than the 2.125. it seems much more stable at speed and controllable and definitely worth the modding. I tried 30 psi but the slight rub got a little worse so I'll try that again once I've seated the tyre a bit better. Also no need to life weigh up and down dropped curbs as the tyre takes it. MCM5 seems a little tamer too but maybe I just need to get used to it again. I have a small rub on one corner and I need to take a few more mm off the transparent part, see the photo and the slight mark on the tyre. Just below (as looking at photo) the H. Looking inside it looks like cornering at 18mph makes the tread slightly make contact with the plastic web on the inside of the main shell, there's plenty room so I'll just let it wear down a little as never cut anything off the shell. 1 Quote
alcatraz Posted February 26, 2020 Posted February 26, 2020 Check that the tire is nice and center. Eyeballing the bead/rim interface is not always enough. Try looking at a small gap between tire and shell while spinning. Then you know which way to nudge the tire to get it centered perfectly. 1 Quote
Delmeekc Posted February 26, 2020 Author Posted February 26, 2020 6 hours ago, alcatraz said: Check that the tire is nice and center. Eyeballing the bead/rim interface is not always enough. Try looking at a small gap between tire and shell while spinning. Then you know which way to nudge the tire to get it centered perfectly. Did exactly that and she is on true now. 2 Quote
Delmeekc Posted February 26, 2020 Author Posted February 26, 2020 10 hours ago, Delmeekc said: Did exactly that and she is on true now. Balanced too now to within a gram. 2 Quote
alcatraz Posted March 3, 2020 Posted March 3, 2020 Nice. That has to be one smooth and stable mcm5 at high speed. 2 Quote
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