leoho5

Just noticed that the new Verge x11 is using the SRAM XD Driver freehub body which allows the mounting of a 10-42t 11 speed cassette.

The 10t cog and wide gear ratio seem like a dream. Anyone mount an XD driver on their folder? It would be quite a commitment going to a new driver body and no longer being able to mount traditional cassettes.

Nightdiver

Many hubs allow the driver body to be swapped out, so theoretically you could swap back to traditional cassettes if for some reason you no longer fancied the XD setup.

Abu Mahendra

SRAM 10-42T = 4.2x
Shimano 11-46T = 4.18x
But I am sure you already know this. Don't know where you are, but here the Shimano goes for $85 here, and the SRAM for $285.

cplager

That's true, but if you're going for high end, 10 is 10% higher than 11. (Well, 9%). And for small wheels, this is often what people are after (I run a Capreo hub and have a 9-26T cassette).

Abu Mahendra

That's true, but if you are going for high end then a SRAM DD will give higher highs and lower lows.

52T / 9T = 5.78
52T / 11T * 1.36 = 6.43

(I run a SDD, 11-36T & a 47T chainring, giving 18-110 GI. I changed the old 52T chainring for a 47T because it had too much top range.)

downtube

The Dual Drive is very heavy, and the wide gear range with small wheels can create super low gears that are not usable.

Thanks,
Yan

Abu Mahendra

A SDD hub is about 500g heavier than a Capreo hub with QR, yes. But I would not characterize it, given its functionality, as 'very heavy'.

As for creating gears that are not usable, well that depends on the design choices if you don't know what you are doing. If you do know what you are doing, you will adjust the chainring and max cog so you don't end up with useless gears, as my example attests. 18GI is a blessing when loaded and climbing steep volcanic gorges. It is far from 'not usable'.

downtube

I agree with the concept of the argument, but I think the implementation may be awkward. You would need big charings on 20" wheel bikes, while 16" wheels would need a 90ish tooth ring.

Thanks,
Yan

Abu Mahendra

I don't follow. A roadbike with a 53/39T crankset will max out at about 130GI. What size chainring with a 406 wheel, 11T cog & SDD would be needed to reach 130GI? 56T. What size with an 9T Capreo cog? 62T

downtube

60T will do it on a 20" 406 wheel, but the 16" needs alot more. I'm looking at the low gear with 11-34 cassette, I couldn't use much less than 25 gear inches.

Thanks,
Yan

Amt0571

I agree on it being heavy. But not about the super low gears. My Dahon has 20" wheels, with a 52t chainring and a 11-34 cassette coupled to a DualDrive and I use both extremes daily. It may not be for everyone, but if you live in a hilly place like me, it makes a huge difference. I no longer spin out on descents and can reach 50km/h easily, and I'm able to climb 15% grades while seated with loaded panniers and keeping sweat under control if they're not too long (which is a must when I commute). It would be difficult for me to go back to a conventional transmission.

On most other folding bikes I find gears are way too low to be useful in most descents.

Anyway, If you feel the range is too much, you can always switch to a 11-28 cassette and enjoy less gaps between gears.

Abu Mahendra

To put in in perspective, a SDD hub is 960g, an Alfine around 1,500g and a Rohloff around 1,950g.

cplager

My recumbent bikes go down to 16". I'd have them go lower if they could easily do so. And while dual drive is heavier, it ain't heavy.

downtube

I loved the idea of Dual Drive until I purchased boxes of them from EPX 10-13 years ago. It was very heavy compared to a standard hub. Additionally I could feel the resistance in the hub, it was not smooth. I searched for the efficiency rating, but never found anything. I kept one DD for myself and built it up with an electric blue rim, but I never used it. I doubt I'll ever use it.

I understand the internals were well made ( according to Sheldon Brown ), and maybe I was feeling lots of fresh new grease packed inside. Regardless touching and feeling it was a big turn off for me.

FYI a wide range cassette 11-42 or 11-44 is lighter, cheaper, probably much more efficient, and gives all the gears I would ever need for a small wheel bike. I'll take a wide cassette over a DD any day.

Thanks,
Yan

Abu Mahendra

Yan, I don't get it. You spec your bikes with Alfines, which are a good 550g heavier than a SDD. And we don't hear you or others bemoan that. When you add up the coget and RD, a SDD is about the same weight as an Alfine, but much more smooth shifting and much wider range. How do you justify the weight and price of an Alfine on your Downtubes, while indicting the SDD? I share your liking for the newer wide range cogsets, but they are not a replacement for SDD. They are a replacement for the likes of the Alfines on your own Downtube models.

SDD hub: 960g
Zee RD: 250g
XT CS-M771 11-36T cogset: 340g
Range: 610%
TOTAL weight: 1,550g

Shimano Alfine 11-speed: 1,665g
Range: 409%

I can't feel the resistance in my SDD I. Perhaps you had the Mark I?

If all you need is the range of a 11-42T cogset, fine, but often the choice is not wide cogset vs. SDD. Once again, imagine a customer of yours wants/needs 18-110GI, how else are you going to get that gear range on a 406 wheel?

downtube

Thanks for the question. I see things differently, the Alfine is a pure internal hub ( DD is in a different class IMHO ). People like internal hubs & belt systems, hence I supply them. I see the DD as a freehub based option, and I think wide cassettes are better, especially for small wheels. These new cassettes systems are lighter and give a nice gear range for small wheels, and you can shift under load ( internal hub systems don't like that ).

I'm not sure what version DD hubs I had, I recall that I purchased about 50 units

Thanks,
Yan

Abu Mahendra

I share your liking for the newer wide range cogsets, but they are not a replacement for SDD. They are a replacement for the likes of the Alfines on your own Downtube models. Wide cogset vs. SDD - false choice


SDD hub: 960g
Zee RD: 250g
XT CS-M771 11-36T cogset: 340g
Range: 610%
TOTAL weight: 1,550g

Shimano Alfine 11-speed: 1,665g
Range: 409%

Range 11-46T cogset: 418%

An Alfine 11 is heavier, more expensive than a SDD drivetrain offering a wider range. A wide cogset is lighter, cheaper and offers ag least as much range as an Alfine. The real question is not why SDD, but rather why Alfine. The real porker given the weight-to-performance, and weight-to-price ratios is the Alfine.

Some of these conclusions also apply to Rohloff which is even heavier and much, more expensive.

downtube

Abu,

The majority of my internal hub customers require a belt drive for use on a boat. These customers are not looking for a cassette/freehub solution. DD can't use a belt, hence I see it differently.

I have never used a low gear under 25 and I have climbed some amazingly steep hills. I lived the the Virgin Islands, which had the steepest climbs I have ever seen. I climbed everything with a 28 or so. Outside of mini's I have never had a bike with a low gear under 25 ( not including mistakes at the factory ). I provide my customers with the things I like in a bike such as: suspension, low gears, quality components. I don't t know that I have ever needed a gear as low as 18 so I am not looking to provide that.

Please understand as I grow, and learn my lineup will change. I am currently sharing my perspective as of today.


Thanks,
Yan