Jipe

81,1" is really short, 78" is even worse !

I have a Brompton with Rohloff (54x13), the 19” to 102” range is really excellent. 102" is about 25% longer than 81.1" !

JRat

The Birdy Rohloff is supplied with 52T / 13T which gives gearing of 19.9" to 104.4"and I'm planning to change the sprocket to 14T which drops the gearing to 18.4" - 97" which is very close to the gearing on my main bicycle. However, a double chainring with 11-32 casette will never give the gearing range of the Rohloff so theere has to be a compromise somewhere. My aborted project to put a double chainring (54 + 38) on a Birdy City (8 speed hub gear) would have given gearing of 22.3" to 97" with a 16T sprocket. 22.3" would be just OK for my worst local hill but it would have been easy to lower the gearing by fitting a bigger sprocket.

Jipe

The slightly longer gear range of the Birdy Rohloff vs. my Brompton Rohloff is due to the slightly bigger wheels and mainly the bigger/wider/higher Big Apple tires.

desmondk07

Hi- Is there a dealer in SG that actually help to convert to Rohloff Hub? If so I am keen to look at that also on my GT.

One qn - has anyone used a larger chainring say 58T vs 13t sprocket on Rohloff? I know is not known as a speed demon but technically the largest gear inch at gear 14 here (118”) would be much longer than most including R20

So at same candence rohloff would be faster? Or did i miss something?

Huggable

Yes, Green Basikal is the Rohdoff dealer in SG. and I think for MY as well.

JRat

I haven't tried using a larger chainring and wonder if this would affect the foldability. My calculation suggests that extra 6 teeth increases the chainring diameter by about 24mm and you could do a visual check on the implications of this. A longer chain would be needed which might affect how easily it can be folded.

You are correct that a larger chainring will give a higher speed at a specific cadence and this applies through the whole gearing range. 58T instead of 52T increases the gearing by about 11.5% which is close to 1 step in the Rohloff gears. If you live in a relatively flat area with no need for the bottom gear or two then I would suggest that you try using a bigger chainring if only to find out if it works.

Jipe

The current chain tensionner arm placed around the chainring limit the chainring size.

Huggable

I'm using a Ridea 56T oval chainring currently, and will be pairing it with at 13T sprocket on the Rodloff hub for a 20" to 108" range.

I have no problems folding with the 56T chainring, but not sure if 58T would be too big for folding.

Huggable

Finally I got to collect my Rodloff after 2 month's wait. Just love the way the close ratio gearbox shifts!

JRat

Enjoy. Shifting will further improve with use and the hub itself will become quieter. Make sure that the Ex-box is fully packed with grease. I find that this helps provide easier shifting.

Huggable

Yes, I'm enjoying every moment with the Rodloff hub!

Do you mean the click box?

JRat

That's another name for it.

Jipe

Does anybody know is (assuming using a SRAM XDR body rear wheel that I have), a 10-44 SRAM 12s XPLR cassette will fit on a Birdy (from what I see on my Birdy with a 10s 9-32t cassette, it seems to me that the chain on the 44t will rub against the left stay) ?

Does anybody know what is the maximum biggest cog size possible ? I have now 32t, would 36t ou 40t fit?

P.S. : this cassette and the XDR body are road/gravel components, not MTB components.

timo888 

Not the specific answer you are asking for, but the variables you could play around with when dealing with that stay are 1) bottom bracket spindle width 2) front chain-ring diameter and 3) granny cog diameter. If you are willing to trade off some power for easier climbs, you could get a smaller front chain ring with your existing cassette and BB.

Jipe

My motivation is to get rid of the original Sunrace hub and cassette and at the same time have narrower spaced gears.

The range of this 9-32t cassette is enough but the hub isn't reliable and the cassette is very difficult to find in spare parts.

I have two options, either go as with my Ti Birdy with a 3T 11s 9-32 cassette for XD/XDR hub and Shimano Ultegra or 105 derailleur that works very well but with the drawback that this cassette is not really available anymore.

The other option is to go with a full SRAM transmission using a 12s SRAM XDR cassette and SRAM road or gravel derailleur but there are only two cassette that give at least the same range I have, the 10-36t and the new XPLR 10-44t (there are also smaller range cassettes, the other SRAM wide range cassettes are MTB and not road cassettes). The 12s offer also closer spaced gears.

soulesss

I have a Birdy Classic BD-1 (unsure which mk), which comes with the fixed 10D unadjustable stem. I'm looking at purchasing a used adjustable stem, which was supposed to fit a Gen 2 Birdy. I have looked around to find any resource on the differences, and have not found much. does anyone know if a stem from gen 2 or 3 will fit a Birdy Classic BD-1?

Another question - what are the actual practical differences between a 10D vs a 25D? is there a guideline... which is suitable for taller/shorter riders?

Thanks in advance!

Jipe

There are two angles for the stem, Comfort 10 degree and Sport 21 degree.

As you can read (sorry its in Dutch but I think its understandable), it seems that the one for Birdy II also fit for Birdy I (there are two other versions for the Birdy III).

The Sport 21 degree fits better for taller rider while the Comfort 10 degree fits better shorter riders.

Note that both adjustable stem have two positions with two different reach values (s (the reach adjustment is done by rotating the top part of the stem by 180 degrees and moving the push button to the opposite side of the stem tube, there are two holes in the stem for this push button)
Pacific Cycles has also a fixed one piece lower 19 degree stem (which because its fixed has also no reach adjustment possibilities, its always the shorter reach).

soulesss

That's good to know! thanks alot!

BabyCowHK

With the default 52T chainring, we can only go with 11-34T cassette max. It was proven with the original B3 10SP Sports model from Pacific Cycles that was on offer 6 years ago. This model has been discontinued.

If you are considering to go with 9T-44T cassette, you might have to consider moving onto a 48T or even 44T chainring for a single chainring setup. You will be getting higher top and low gear ratio but high gear gap as you might already know.

My 3x10 Touring Birdy 3 is using 44T and 11-36T combo without the chain rubbing the rear fork.

I have a friend with a Frankenstein New Birdy Classic running 44T single chainring pairing with a 9-46T cassette. He initially used a Zee RD and eventually switched to SRAM Force AXS XPLR RD. (He replaced the stock v-brake forks with Birdy 2's disc brake forks.)

BabyCowHK

I am running this setup of 56/39T chainrings and 11-34T cassette. 56T will definitely be fine with a 1.5cm gap between the charinring teeth and the tensioner. Foldability is also ok with this setup. Given that my chainrings no longer have the chain guards, I have to make sure the chains are wrapping the large chainring properly.

I never go big-big or say cross chaining so the rear forking rubbing is never a problem to me.

I'm not so sure about 58T though.

JRat

Thanks for this information. I was thinking of resurrecting that project when I have time and inclination. One of the problems I previously encountered was the likely need to dismantle the cranks and to the chainrings out so that the front derailleur would work properly.

BabyCowHK

Sorry that I didn't go through the whole thread, so what's your crankset? It should work just fine if you have the hollow shaft type crankset with a BSA 24 BB. Taper crankset is a no go. It will cause small chainring & big sprocket combo to scratch the rear fork above the fork pivot area. The chain line is too narrow.

This hollow shaft crankset can be directly converted to use a double chainring. The only requirement is to make sure that there is a 2.5mm spacer on the drive side or both sides to balance out the Q factor. And of course the rest of the FD mount and FD itself.

Some crazy mechanics I have seen installed two 2.5mm spacers on the drive side which kind of shifted the chain line too much. Don't make that mistake.

Luna_sea83

Hi new birdy owner here,

Would like to check if any members here happen to install Token bb TK868TBT-119 square tapered onto their Gen 3 bodies here?

I am looking to use a particular crankset H&H square tapered instead of the common Ridea crankset and bb that everyone here seems to be using for their upgrades.

thanks in advance!

Jipe

I do not think its a good idea to go back to the old square tapered BB.

These square taper are heavier and causes many problems like noise.

Moreover, many brands do not respect the JIS or ISO standards (ther are two official standrs for square taper) and mounting a square taper crankset from one brand on a square taper BB from another brand even if both are JIS or ISO often causes problems, the BB square going too far or not far enough in the square hole of the crankset.

The Birdy BB is a standard one, you can mount any standard BB in it, no need to use a Ridea BB on the Birdy.

There are excellent modern crankset from the main brands Shimano, Campagnolo (look ate the gorgeous Super Record carbon/titanium, its easy to find the old 5 arm model), SRAM. And also smaller brands like FSA.

The price/quality ratio of these crankset made/sold in much bigger quantities than the Ridea is much better.

My Birdy Titanium was factory equipped with a FSA SL-K Light carbon crankset with external bearings which is lightweight and fits perfectly in the Birdy.