Weighing the options on an HP Velotechnik

HP Velotechnik Carbon Fiber Boom

Recently, a customer asked me what we could do to make an HP Velotechnik Grasshopper fx a bit lighter, using the options readily offered.  We looked at the weight difference for the front fork (with shocks), seats, rear shock and front boom.  For the suspended front fork and rear shocks, there are improvements in performance as well as differences in weight.

From the following, not including the front boom with/without derailer mast, if we chose the lightest option, we could lessen the bike weight by 28.93 oz (1.81 lbs).

Front Boom with or without derailer mast
If you get a Rohloff Speed Drive or SRAM Dual Drive, choose the aluminum boom without the derailer mast for weight savings at no additional cost.  Sorry, but I don’t have two unmounted booms on hand at this time to compare the weights, but I’d give it two to three ounces.

Seats
Body Link w/ foam pad – 1,885 gms / 66.5 oz
Ergo Mesh – 2,055 gms / 72.5 oz
__Difference: 170 gms / 6.0 oz

Front Fork with Shock
Spinner Grind 2 AL (better performance) – 1,610 g / 56.79 oz
__Difference from standard front fork and shock: 250 gms / 8.82 oz
Meks SASO Carbon AC (best performance) – 1,710 g / 60.32 oz
__Difference from standard front fork and shock: 150 gms / 5.29 oz
Spinner Grind 2 (standard, good performance) – 1,860 gms / 65.61 oz

Rear Shocks
DT Swiss XM 180 Air Shock (best performance) – 172 g /  6.07 oz
DNM DV-22 (Standard, good performance) – 400 g / 14.11 oz
__Difference: 228 g / 8.04 oz

Front Boom
Carbon Fiber front boom (lightest):
__Difference from standard boom: 170 gms / 6.07 oz

If one were to choose the options in terms of the most weight savings for the cost, the order would be:
1 – tied) Front boom without derailer mast
1 – tied) Body Link seat
2) Spinner Grind 2 AL
3) Carbon Fiber front boom
4) DT Swiss air shock (but man! that DT Swiss air shock is awfully sweet)

Have fun and stay healthy,
Robert
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Robert Matson
New York City Recumbent Supply
The Innovation Works, Inc.
copyright 2012 Robert Matson