Hello everyone,
I am looking for advice from anyone who has experience with Honda NSR 125 suspension geometry, especially regarding rear wheel conversions.
I own a Honda NSR 125 JC20. The bike originally came with an 18-inch rear wheel, but I have converted it to a 17-inch rear wheel fitted with a 140/70-17 tyre.
The problem I am trying to solve is the rear suspension geometry after the conversion.
I have measured both original Honda shock absorbers from eye-to-eye (centre of upper mounting hole to centre of lower mounting hole):
- Original JC20 shock: 265 mm
- Original JC22 shock: 295 mm
Because the JC20 was designed around an 18-inch rear wheel and the JC22 around a 17-inch rear wheel, I have been studying the geometry differences between both models.
After comparing the wheel sizes and calculating the changes in rear ride height, I have concluded that the ideal shock length for my particular setup would be approximately 285 mm eye-to-eye.
Therefore, I am searching for a shock absorber close to 285 mm, but I have been unable to find any manufacturer offering a suitable unit for the JC20 in that length.
My questions are:
- Has anyone converted a JC20 from an 18-inch rear wheel to a 17-inch rear wheel?
- What shock length did you finally use?
- Did you install a JC22 shock, a custom-made shock, or modify an existing one?
- What was the final eye-to-eye length?
- How did the bike handle after the conversion?
Any measurements, photos, recommendations, manufacturer references, or personal experience would be extremely helpful.
Thank you very much for your time and assistance.