Hi All

I am building a fast light folding bike and, I am interested to know if there are other similar bike enthusiasts out there. My build is full carbon with full sram red 10 speed group set 52 up front and 11-28 rear casette. Carbon seatpost carbon bars carbon tri spoke 20" 406 wheels with Schwalbe pro one addix TLE (tubeless) 28mm tyres and speed play pedals. The frame and fork weigh 1.68kg all in. When it is built early next year it should come in sub 7kg. Does anybody else have a similar build either going on or completed? I'd so I would like to pick your brain on a few pointers...

Thank you for reading
Pietro

Bike Friday makes a very expensive version of the pakiT @ 15 lbs. You can see the specs here: https://www.bikefriday.com/bicycles/configure/2460. They also make one with an Alifine drive. Lots of carbon, you can sub titanium for some things. Unfortunately you can't pick their "brains" but you might find the various spec options interesting or useful.

I got to 8.2kg with a Bike Friday Pocket Rocket Super Pro. (includes pedals)
https://www.google.com/url?sa=t&rct=...oPZ6PTGJhpafSJ

I know there are lighter builds that swap a carbon fork+steerer tube, bringing the bike down to around 7.5kg

Been there, done that for me, trying out various folding bikes and mini velos over the years.
IVE, Raleigh MV, Moulton TSR, Bi-fold "Dahon/tern" clones, BF Pocket Rocket.
I ride these with road groups mostly on a Sunday (Sat being the road bike ride)

Unfortunately, speed is in conflict with folding as a larger wheeled bike does have the advantage when it comes to speed.
Be it easier to achieve high gearing with common available parts to better wheel rollover on not ideal roads, and more repeated losses with more rpm (for smaller wheels).

451>406>18" when it comes to speed, but that does mean folding size takes a hit.

To me, most builds will be based around the same few components, since the frame will be what it is with the most gain being a fork and seat post change. So my few cents :
1. Look for a frame that is inherently light (alloy, carbon, joint/fold type )
2. Potentially swap to lighter fork , seatpost , appropriate saddle
3, Can't run away for the standard groupsets (ie. Ultegra, Rival, Force, DA, Red). for what its worth, Rival set with Red crank is lighter and cheaper than a full Force (cable versions )
4. The rest of the weight savings will be high price, low gain items like pedals, brakes, Ti screws.


In the end, I consolidated to keeping my Raleigh MV as its my beater bike for commute and wet weather training and a Change Bike (650b folding) for travels, Sunday road rides, gravel.
Change Bike 650B - Bike Forums

Pinholecam - How much faster did you find the 451 wheels over the 406 wheels?

I have a Moulton TSR that doesn't get split that often so could stand the slight reduction in practicality. I have seen a 451 conversion on this forum so know it is possible. I prefer the manoeuvrability of the Moulton over my road bike when I am commuting but wouldn't mind a bit of extra speed.

My gauge in speed is always the rides I do, usually with other riders on road bikes.
So comparatively, I will say that the 406 tends to meet a limit in the pack sooner than the 451, so if there is a surge or slight downslope or speed pick up to a endpoint, the pack picks up a lot of speed and the 406 runs the risk of not having the gear (at reasonable cadence) to keep up.
Maybe an ave 1kph difference in a sustained 20-30min effort and 1.5-2kph one over 10min.
Top speed wise, I would say about 3-4kph.
My Raleigh MV was 406 and I converted it to 451, so the difference is certainly there.

Yes, the maneuverability of smaller wheels is a plus for me too especially in commutes with traffic (also getting into lifts and narrow corridors)
You will need to find suitable brake calipers for the TSR if converting to 451.


Recently, I have been thinking of a custom breakaway Ti with 24" or 26" to get the best of a small bike that can pack and not too far in terms of speed for road rides with the option for wide tires on light trails (I already have a 700c bike w/ breakaway system, but the maneuverability and smaller pack size of 24" or 26" interests me)

yes, that's pretty much the "standard procedure" (there should be a ASTM or ISO standard about it).

The comment on Sram mix is so true; I did that for my gravel (Rival shifter and derailleur and force crank) and I got most of the weight saving out of the crank. it is even truer with red.

One thing to mentioned about carbon, always get a recognized manufacturer product, not a ebay jobby... a carbon handle bar for $20 when the equivalent aluminium is $15 is not a good choice. Also, when I was looking at carbon seatpost, I found that the litepro aluminium (~$30) for Dahon/Tern was 50g heavier than the carbon version >$100. My breakfast is heavier than that difference.

I took most of the weight out of a dahon with
1- Tyres
2- Rims
3- Crank
4- seatpost
5- stem
6- handlebar

I could have gone saddle but I value my back carriage comfortable over light weight...

I currently building mini velo and I am still undecided whether I go light road version or BMX style...

If you want more speed, you could simply swap the chainring and have 4 teeth extra to shift your gearinch.
The advantage of the 451 over 406 is the better rolling over bumps. you could compare it to the difference between 700c and 650b
for example: 32-622 (700C) ~ 50-584 (650b) similar gearinch - similar speed when rolling resistance is equivalent (My 50-584 conti are faster than my 38-622 G-One because 1/3 less rolling resistance).
however 35-622 (700C) vs 35-584 (650b), 650b will be slower but will accelerate faster.

in the case of 406 vs 451, it is the same story, at equal rolling resistance, a 47-406 will be as fast as 25-451. But 35-406 vs 28-451 will be slower (factor 1.07) which as I said you can shift with the chainring
With 35-406, you feel more cobble vibrations than you would with 28-451

Thanks. There are two factors here that can be helpful. The first one is the higher gear inches possible, but in my case I spin out at around 40kmh so it isn't that often (unless I have the wind behind me and going downhill). Most of the time I am in the middle gears and I am never in the peloton.

The other is whether a 451 wheel is intrinsically faster, including for the reasons you suggest. Or perhaps it is just in the tyres. I use Schwalbe Marathons for normal commuting and winter riding, but have some Schwalbe Ones that I might try next summer.

on my gravel I spin out downhill because on 700C (shimano hub), I run 36x11-46 (21.9 to 91.7 GI) as I'd rather go up a offroad hill rather than going flat out down hill. With 650b, I don't; it has XD hub so I run 36x9-46 (21.1 to 107.7 GI). I could swap the chainring to 32 to get a MTB set as go up hill better...


If you do that just because of tyre size, it is not effective. Conversion would involve new wheels and rim V brake adaptor or new calipers.