Buckethead808

I bought a Downtube 8H recently thanks to a price drop, and from looking at the forum, at least several of you did the same. I thought it might be nice to have a thread (separate from the existing, very large Downtube thread) to share mechanical tips, accessory picks, modifications, and so on. The 11H appears to use the same frame and most of the same parts as the 8H, so things that apply to one model should mostly apply to the other as well.

Setup
My 8H was purchased summer 2021. Downtube has a set of new bike instructions that cover some of the initial setup, but it doesn't mention belt drives at all. I found a good video from Bike Friday (that I can't link to yet) explaining how to tension the belt and check (roughly) that the tension is correct. They're working on a PakIT in the video but the setup is similar to the 8H.

Mine needed a few adjustments out of the box, these may be obvious to those with more experience but may help someone:

1. The belt tension was much too high. The Bike Friday video above was enough for me to get it close to what it should be, but Gates sells a $15 tool that will measure belt tension more precisely, I may pick one up.
2. The rear wheel was mis-aligned, the front of it pointed to the left side of the bike. Since I had to adjust the belt tension anyway, not a big deal to fix the alignment.
3. The fenders were off-center and too high, rubbing against the V-brake boots. Lowering them is easy.
4. V-brakes were a bit tight. I wanted to give them a little toe-in anyway.

Accessories
I haven't owned a bike in a while so I'm starting mostly from scratch, I don't even have a lock yet. I'm planning on the Abus Granit X-Plus 540, it seems like smaller U-locks like the Kryptonite Fahgettaboudit and the Abus 54 Mini are too small to cover the distance between the rear wheel and the smaller tube going from the crank to the "top" tube (not sure if folders have agreed-upon names for the various tubes?) while still leaving room to actually lock the bike to an object.

Cargo Carrying
For the bike's front cargo mount, I looked at both the Brompton block and Klickfix systems. It seemed like there are more Klickfix-compatible accessories available, so I ordered the Tern G2 luggage truss, which should work with the mounting holes on the front of the 8H and has a Klickfix mount point.

Anyone else have any tips for a new 8H owner who is getting back into biking after a long absence?

uralik

Couple of advises which can be helpful:
1. If you regularly commute, then always check your tire pressure, with a pump dial / not with your fingers. Correct pressure helps to avoid pinch flats and punctures in general.
2. Stock tires I had (kenda) are not really puncture resistant so I bought Schwalbe marathon plus and I have had no punctures in NYC / Brooklyn since Feb, really like these tires.

kiwi38

Does anyone know if the Dahon valet luggage truss for the front of the bike is compatible with the 8H? They both have 3 holes but not sure whether the screws that come with the valet truss are of the same size as the 3 holes on the 8H?

Also if I wanted to change the tires to puncture resistant ones from Schwalbe, which models should I be search for for the front vs. rear wheel? I know the front one is 1.5" and the rear one is 1.75"... Confused over the selections...

Thanks in advance!.

Buckethead808

I don't know about the screw thread size but as long as the mounting holes have the correct spacing, a trip to the hardware store can fix the screw size problem. I had the same problem with the Tern G2 luggage truss: the mounting holes line up fine (the 8H has three holes with 15mm between each, the truss has two holes 30mm apart), but the included screws are too fat. I just picked up a couple new screws.

The 8H's front and rear wheels are the same dimensions: 20" diameter x 1.5" wide. They come with a 1.5" tire mounted in the front and 1.75" in the rear (40-406 and 47-406 in ETRTO terms), but you don't have to stick to those exact sizes. From uralik 's photo in another thread the Marathon Plus tires they mentioned look like 47-406s front and rear. I was planning on replacing my tires with 47-406 Marathons (not the Plus version) soon-ish.

uralik

Regarding the tires - I have Schwalbe Marathon Plus 20" City Tyre - SmartGuard 1.75 width, bought each for $37 from chain reaction online store. They are pretty amazing!

sslonkosky

The 8H comes with Kenda tires, not Schwalbe.

Yan has been writing lots of blog posts recently. He says that he used to supply all his bikes with 1.75” wides tires, but now uses 1.5” in the front and 1.75” in the rear on most models. He and his friend Paul tested this and found that the bikes ran an average of 1.5 mph faster. https://www.downtube.com/pages/tires-mix-matching/

I wonder if anyone else has tested this.

I’m thinking of using 2.0” Schwalbe Big Apples, though maybe just in the rear with a Schwalbe 1.5” Marathon in the front.

uralik

Would be cool to see the actual 'experimental' protocol where they observed 1.5mph increase. Otherwise it doesn't make much sense. Coming from MTB world I always assume that I would rather lose traction of my rear wheel rather than the front -- if the front goes sliding then there isn't much I can do. Thinner front tire would anticipate the latter behavior imo. Now when it comes to 1.5 mph increase, then idk at what condition this bike with such gear ratio can be that fast such that 1.5 average difference would be noticable... As you may seen I ride this one with front hub motor and on peak *comfortable* speed around 40kmh on the last gear the cadence would approach 90-100 rpm. Going faster would be only feasible if you go downhill without pedaling. Losing traction of your front wheel can be pretty much fatal in such situation at least for the bike.

So I would say mixing width is not a bad idea, but on this bike I personally chose to use same width, and I didnt notice any difference with stock tires configuration in terms of speed / traction .

kiwi38

Dahon sells a landing gear product which is basically a luggage wheel that allows the the folded bike to be more easily rolled. I saw the Downtube 8H has a trapezoid shaped support that comes installed by default. Do you think the Dahon landing gear could be compatible (after removing the trapezoid)?

Also, any thoughts on adding a magnetic buckle to make the bike stay folded?

uralik

Some updates:

- I have installed the steel fork from ThorUSA which is the OEM from dahon touring and omg how much better the steering feels. I have added simple disc brake for my front hub motor and it works really well.

- Even more interesting update - the brompton adapter which works for our downtubes! You can find one on aliexpress, was about $15 including delivery. I have also bought the brompton front rack replica from aliexpress as well (about $25 or so). The included screws and bolts did not work that well so I used some others. The front rack was a bit wobbling when installed but this easily fixed with some extra washer in the racket. I may share photos if it can help someone. After that it works *really well*.

You can see both upgrades on this photo: ht tps://imgur.com/a/3kCgYpd

Cheers!