I think I've finally found the answer. Have I got it right?

[Deleted member 121159]

I've been searching for a way to get the lowest possible gearing on my bike with BB86 pressfit BB. It was a total mistake to get a pressfit BB bike. Not because of the BB itself (I actually like pressfit BBs), but because of the limited range of options when it comes to chainsets. I'm currently running GRX 2X 46/30 chainset. As far as I know, the lowest I can go with 24mm (Shimano style) chainsets is 42/27 using a Sugino Ox chainset. To be fair, that would be low enough for me, but I'm not ready to fork out £500 or so on a chainset!

I think I might have found the solution to my problem.

https://www.aliexpress.com/item/100...f116741791182074687ed521!12000030538998854!sh

This is Senicx PR3 chainset that accepts Sram-style direct mount chainrings. But instead of a 30mm DUB axle, it uses the normal 24mm axle so it interfaces with BB86. Then to this chainset I can mount...

https://www.aliexpress.com/item/100...00027733149111!sea&curPageLogUid=gMSgO3oA3oNy

If it works, I can achieve 36/26 at the front! Then I can mount 11-42 at the back (with Wolftooth roadlink), giving me astonishing sub 17 gear inches with 37mm tyres.

Can anyone see why this might not work? The Senicx is well-received online, even though it's quite heavy. I'm not sure what the quality of the chainrings are like, but I'm ready to live with slightly less smooth shifting for easy gears.

 

[Peter Salt]

Sounds like an e-bike may be a better solution?

 

[Deleted member 121159]

Sounds like an e-bike may be a better solution?

Now I knew some of you would say something snarky like that!

Well those of you who like hard gears and going fast should maybe just get a motorbike

 

[Cycleops]

A super granny set up. Why not?
Steel chainrings by the look of it. AliExpress stuff is usually high quality. but should work.

 

[Ajax Bay]

Put me into the snarky box too with @Peter Salt .
"I've finally found the answer. Have I got the question right?"
Why? Just why? Who are you trying to astonish? [". . . giving me astonishing sub 17 gear"]
What are you trying to climb which needs a <17" gear?
If this is just 'how low a gear can I get' project, crack on.
With disc brakes, why not fit some 24" wheels: that'd make the gear length shorter.

 

[All uphill]

I'm not in the snarky box, but I don't have a solution for you, or a comment on your proposed solution.

My lowest gear on my tourer is 21" and there have been a few times when I'd be happy to have something lower, even if the front wheel would lift off the road.

Have you spoken to the guys at Spa?

I wonder if you could keep your existing FD and crakset and use a 50t cassette?

 

[Ming the Merciless]

As far as I know, the lowest I can go with 24mm (Shimano style) chainsets is 42/27

Shimano do a 34 / 24 double

 

[Deleted member 121159]

So, to respond to the comments above:

Why look for something so low/easy? 46/30 combined with 11-40 (my current setup) is simply not low enough for me. I like going slow but I also like climbing. I'm 6'2 and weigh 13 stones so that may have a role to play. I am very slow by road cycling standards (12-13mph on average over 30-60 miles, 10-11mph if very hilly). My bike weighs 14kgs with all the accessories. It's got massive slow tyres. And I like to carry food (I mean real food), sit and rest whenever there's nice scenery. I'm that type of cyclist. And scenic mountain roads are steep! Think Jack Thurston. I never use 46-11 and almost never use 46-13, so it means I'm effectively running a 9 speed system, which is stupid when I'm paying for 11 speed components. Now with 36/26 chainrings, I will use all the sprockets!

Based on BikeCalc.com, 36-11 at 90RPM will give me 24mph, which is plenty for me (when it's flat). I don't pedal going down.

Now, Spa cycles/Shimano MTB components. I can't use them. Spa uses square taper and mine's pressfit. Shimano MTB cranks can go on on BSA68 but not BB86, as far as I know. The axle will be too long for BB86, spacers will technically allow me to convert BB86 to BB92, but it wouldn't work as it'll be a poor pressfit and the BB will likely fall out.

 

[presta]

Can anyone see why this might not work?

Your top gear's only 88", is that ok?

What are you trying to climb which needs a <17" gear?

Hardknott & Wrynose?
My 11-34 & 22-32-44 transmission gives me 17.5" to 108"

 

[Deleted member 121159]

Your top gear's only 88", is that ok?

Hardknott & Wrynose?
My 11-34 & 22-32-44 transmission gives me 17.5" to 108"

Yes and yes. There's some >20% climbs around Abergavenny. I couldn't even get my bike going.

Can't use touring triple unfortunately as the axle length is the same as MTB cranks.

 

[rivers]

A cheaper/easier option may be to go for a mullet drive train. Road shifters with a MTB rear derailleur. It's the current set-up I have on my gravel bike. Look for a rear derailleur with a 50 tooth capacity, figure out which one of these you need, get an appropriate cassette, and away you go. Most people go for a 1x with a mullet set-up, but i have 2x and it works brilliantly.

 

[Deleted member 121159]

A cheaper/easier option may be to go for a mullet drive train. Road shifters with a MTB rear derailleur. It's the current set-up I have on my gravel bike. Look for a rear derailleur with a 50 tooth capacity, figure out which one of these you need, get an appropriate cassette, and away you go. Most people go for a 1x with a mullet set-up, but i have 2x and it works brilliantly.

Interesting info about the 'shiftmates', I didn't know about them! I don't know if this is really a simper/cheaper option, though. I'll need a new derailleur, a cassette and a shiftmate. With the chainset option, all I need to do is change the chainset. Also big gaps between gears and will still have the problem of having gears I don't need (46-11, 46-13).

Having said that the main reason I didn't go with this setup was that I didn't think it would work due to exceeding derailleur capacity massively (50-11+46-30=55T). I'd be interested to see photos/videos of your setup!

 

[rivers]

Interesting info about the 'shiftmates', I didn't know about them! I don't know if this is really a simper/cheaper option, though. I'll need a new derailleur, a cassette and a shiftmate. With the chainset option, all I need to do is change the chainset. Also big gaps between gears and will still have the problem of having gears I don't need (46-11, 46-13).

Having said that the main reason I didn't go with this setup was that I didn't think it would work due to exceeding derailleur capacity massively (50-11+46-30=55T). I'd be interested to see photos/videos of your setup!

You can read about it here: https://www.cyclechat.net/threads/mullet-drivetrain-conversion.285302/

 

[Deleted member 121159]

You can read about it here: https://www.cyclechat.net/threads/mullet-drivetrain-conversion.285302/

Thanks for sharing.

 

[Deleted member 121159]

Senicx PR3 cranks + 38/28 chainring + 36/26 chainring ordered. Almost exactly £100 including shipping and taxes.

I'm pretty sure there's a lot of interest in low gearing on road/gravel/touring bikes. Hopefully I can show that this setup works!

The main advantages of this over using a super wide range cassette (such as 11-50) would be that 1) I can keep using 11-40 or even 11-36 so maintain narrow jumps between gears, 2) use all 11 sprockets, 3) perhaps smoother front shifting due to a smaller (10t) gap? Plus, the only aftermarket component required is Wolftooth roadlink.