lighter-feeling front end


rayivers

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CT, USA
When I first started riding electric in the summer of 2014, I was a little disappointed at how heavy the front end felt as compared to my ICE dirt bikes. I tried a number of things and kept the ones that worked, ending up with a bike that popped the front up easily under 25mph even when traction was limited. This was a huge improvement, and adequate most of the time.

In early 2018 I made the giant upgrade to Alta and immediately loved the bike, but the front-heavy 'electric feel' was back - so Round 2 of mods began. Below is my 'mod strategy' based on my experiences with the previous bike, brief list of what I did to the MXR, and how well each thing worked relative to the others.

Strategy, in no particular order:

a) modify front/rear weight distribution, static & dynamic
b) reduce anti-squat forces
c) improve RW traction
d) increase RW torque (not really needed with the Alta, but I tried 11/60 sprockets anyway)

Mods I ended up with, from most to least effective:

1) triple clamp offset changed to 18mm
2) handgrips moved rearward (#1 above, rearmost TC bar-clamp position, Pro Taper Raptor bars)
3) 18mm shorter wheelbase (@ 3mm from #1 + 15mm from shorter chain)
4) 12 / 48 sprockets, done at same time as #3
5) Cannon Racecraft 5.8 spring
6) wider rear tires (4), 2.50 rear rim

As with the other bike, effects were cumulative. A 'tipping point' was finally reached where previous small gains suddenly resulted in a noticeably lighter-feeling front wheel in most riding conditions. IMO there's still room for improvement, though.

I'm currently working on a DCC blow-off valve, Race Tech SMGV 5003 piston & shims, and lowering spacer for the WP shock. Hopefully these will have at least some effect on b) above. I may also try moving the pegs back, which helped the other bike quite a bit.
 

Philip

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Lake Havasu City, AZ
1) triple clamp offset changed to 18mm
Doesn't reducing the offset from 22mm to 18mm move the front wheel back, moving the weight bias further forward?

Maybe it just shortens the wheelbase and makes it easier to lift the front wheel, despite the weight distribution.
 

rayivers

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Location
CT, USA
After I took my steering stem out of the bottom triple clamp, rotated it 180°, and reinstalled it, the steering stem and fork-tube centerlines were 4mm closer together, but the steering-stem centerline had not changed relative to the frame. This means the front-end steering and rotating mass - a significant weight - had moved rearward 4mm. I'd like to try moving it back another 4mm. :)

From page 70 of the 2018 Alta manual, with my comments in parentheses:

"Standard setting is with the steering stem offset to the rear (more fork offset / less trail, per MXA); the stem can be positioned with the offset toward the front (less fork offset / more trail, also per MXA). As-shipped with the stem offset towards the rear, the bike has less trail and therefore quicker steering."
 

rayivers

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Location
CT, USA

Thanks! I looked around online and I'm not sure it's available for big-axle forks like the AER, and their site appears to be down (e-axle.com). I did find the Bosch eAxle though :), which reminded me of the Turbo Drag Axle. When I was a kid a guy had one in the next town over, it ripped itself off the car and ended up stuck in a tree. Nothing like a 1,300hp 60K-rpm rocket turbine to spice up your day, and a kart version was available too. :D

Sorry for the shameless hijack.
 

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