Hello, i plan to change my road bike crankset, the Shimano Sora FC-R3000, 9-Speed, 50x34T, 170mm, my bike name is Cube Attain Pro Disc 2018, you may find specs of it in google, as far as i know i have to install mtb bottom bracket, it is press fit bb and as far as i know mtb bb are longer/wider than road bb the question is that if does the distance spacers will come with bb? i look whole google for the 2,5/5mm spacers for press fit bottom brackets and i cannot find one, the other question is how to unmount that bb that is currenlty with my bike and is it risky? for what i have to be patient while doing this? the crankset i plan to install is Shimano FC-U6000-2 CUES 175 mm, i would gently ask if also the front derailleur will be need to swap it to some mtb derailleur? if so what are you recommendations? i would like to those who did installed mtb crankset in a road bike to share with me with their experience, i do not want to make any mistake, thanks in advance.

Why do you want to do this?

i had 36t highest cog in front crankset in my mtb bike, and 12-21t 8-speed casette, its hard to explain how much important it is to have proper gear for every road tilt angle, also on that setup when you want to drive faster, you just put higher gear and just drive faster without need to put more force into pedaling, when i put this setup to my mtb with road tyres my average speed increased by 3-4km/h on the road, besides i think that default road bike cranksets and casettes setups are for horses and for steroid takers, i have thin legs and i love highest cadences possible, arround 105-115 rpm

Ahh, lower gearing. OK.

Since you have Sora stuff on there, I'd look into getting a Sora triple Crankset/front derailleur/front shifter (bottom bracket if needed - I'd need to look into BB requirements for the cranks.

It comes with a 30T small ring, 39 middle and 50 big. If you find the 50T big ring useless you could always grind the teeth off and it'll serve as a bash guard.

i plan to install Shimano FC-U6000-2 CUES 175 mm 36-22t crankset, and 12-25t 9-speed casette in rear, i have on my favourite track a quite steep uphill, like 50m in 800m, and 1:1 gear ratio i have current, i have 34t largest sprocket on rear i found it too heavy for me

Shifting an MTB double with a road double brifter and front derailleur has historically been problematic, I'd have to dig into the situation with cues, however.

A 6.25 % grade? And a 34x34 is too high? Just trying to understand why you want to make such a change. Seems like if you had a long cage derailleur you could add a bigger cog in the cassette.

i do not want to have bigger cog in the casette, i just want to benefit from 36t largest cog in crankset, that allows me to put tighter-graduated casette in the back, starting from the 25t cog which is +/-1% equal equivalent of my 50/34t current setup, i had 36-22t crankset in my old mtb that currenlty is used by my brother, and 12-21t casette, its amazing how well it works, want to ride faster? just shift the gear up, you will feel just little more resistance on the pedals but low enough to still keep your favourite cadence, which for me oscilates between 105-115 rpm, i have quite thin legs and i hate low cadences, i dont have enough strength and my current setup require from me to be both low and high cadence cyclist, on that mtb i remember i was overtaking the electrical scooters on the bike lanes in my city.

I was just suggesting switching the cassette might be a simpler, less expensive way to get a lower gear. Good luck with whatever you decide.

Won't an 8 or 9 speed Shimano MTB rear derailleur and 9 speed MTB cassette work with that Sora 9 speed shifter? I know they work with other Shimano 9 speed shifters. Then OP could use a 11-32 or 36T cassette with his existing crankset and shifters. That stuff is really easy to install and not very expensive.

[edit]: I see this has been suggested already and declined by the OP. But I'll leave this comment in in case the OP benefits from a more detailed suggestion - or maybe a future person will.

OP:
- Use an online gear calculator to determine what gearing you need, after riding any bike that has the low and high gears you desire.
- Make sure the new crank arms are the same length as before, unless you intentionally want to change this for your leg length. The trend in recent years has been toward a bit shorter crank arms.
- Make sure the "Q-factor" is acceptable for you; This is lateral pedal spacing, and mountain cranks typically put the pedals farther apart than a road crank, in order for the crank arms to clear the chainstays.
- Make sure the chainline is correct with the new crank. This is distance from center of frame to center of chainring(s), which should line up with the center of your cassette. For example, my road crank on 7-speed 130mm O.L.D. rear, has 43.5mm chainline.
- Look at your options; When I upgraded from a single crank to double, I tried the 2-piece hollow-spindle design with external bearings, and LOVE IT, for many reasons I find the setup superior over taper spindle bottom brackets. For the external bearings, try to choose a common standard, as each design requires a different wrench; I went with "ISO External" standard, very common.
- Make sure that replacement chainrings are low cost and available for the BCD pattern of your new crank.

there is no 16-34t shimano 9-speed casettes besides i want also to reduce the weight by doing this and larger sprockets wont make my bike lighter

I totally get the bit about having low gears and tight cassette gearing jumps. I run 12-23 on a couple of my bikes. I started getting old, so put 13-26 on my Lemond. I have 50/40/26 on the front on it now, for a 1:1 low, and that bike weighs about 21 lbs with my lightest aluminum wheels on it. 2001 era Shimano 105 components on it.

If you had a BSA Bottom bracket I'd suggest looking for a low miles 5503 crankset/brifter/front derailleur, but if you really have a pressfit unit, I'm not too well versed on that nonsense

If you're not too picky about your left shifter another option would be to get a Suntour Barend shifter to manage the MTB double, and get a nice brake lever for the left side. You may want to consider posting this query in Bike Mechanics subforum, someone there might have experience shifting CUES MTB cranks with Road double shifters and Front Derailleur.

What does your current bike weigh? (edit: ooh, 99 spokes claims 23.1 lbs, lighter than I expected for a Sora bike)

imagine a nice light 1995-ish full rigid MTB would be your best bet. If you have a decent used bike market where you live, you can get stuff like Cannondale M900 that weighs in at about 23 lbs (10.43kg). Gary Fisher Pro Caliber what pretty light in the mid-90s, a lot of Konas were around 25lbs. Kleins were light (sometimes expensive in used market).

Here's my partial list of sub 26lb MTBs (some have front suspension) (pasting from spreadsheet will probably be a mess, but...

<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> Info culled from bikepedia.com. Sticking mostly to the more widely available brands.



Make Model Weight Link 1995




Barracuda




A2E 25.30 https://www.bikepedia.com/Quickbike/...spx?item=32048

A2M 25.50 https://www.bikepedia.com/Quickbike/...spx?item=32050

Cuda Comp 24.30 https://www.bikepedia.com/Quickbike/...spx?item=32056
Cannondale




M900 22.40 https://www.bikepedia.com/Quickbike/...spx?item=32126

M500 23.10 https://www.bikepedia.com/Quickbike/...spx?item=32124

Killer V 500 23.50 https://www.bikepedia.com/Quickbike/...spx?item=32118
Gary Fisher




Mt. Tam 24.60 https://www.bikepedia.com/Quickbike/...spx?item=32242

Procaliber 23.10 https://www.bikepedia.com/Quickbike/...spx?item=32244
Jamis




Dakar 25.50 https://www.bikepedia.com/Quickbike/...spx?item=32330

Dakota 24.75 https://www.bikepedia.com/Quickbike/...spx?item=32332

Dragon 24.00 https://www.bikepedia.com/Quickbike/...spx?item=32334

Exile 26.00 https://www.bikepedia.com/Quickbike/...spx?item=32337
Kona




A'a 25.50 https://www.bikepedia.com/Quickbike/...spx?item=32374

Explosif 24.40 https://www.bikepedia.com/Quickbike/...spx?item=32376

Kilauea 24.80 https://www.bikepedia.com/Quickbike/...spx?item=32381

Ku 23.80 https://www.bikepedia.com/Quickbike/...spx?item=32383
Klein




Adroit 20.80 https://www.bikepedia.com/Quickbike/...spx?item=32365
Marin




Bear Valley SE 24.50 https://www.bikepedia.com/Quickbike/...spx?item=32407

Eldridge Grade 23.50 https://www.bikepedia.com/Quickbike/...spx?item=32415

Indian Fire Trail 22.50 https://www.bikepedia.com/Quickbike/...spx?item=32424

Pine Mountain 23.00 https://www.bikepedia.com/Quickbike/...spx?item=32448

Rocky Ridge 23.00 https://www.bikepedia.com/Quickbike/...spx?item=32456

Team 23.00 https://www.bikepedia.com/Quickbike/...spx?item=32465

Team Ti 22.50 https://www.bikepedia.com/Quickbike/...spx?item=32473
Mongoose




IBOC Comp 25.80 https://www.bikepedia.com/Quickbike/...spx?item=32489

IBOC Pro



IBOC Pro SX 25.80 https://www.bikepedia.com/Quickbike/...spx?item=32492

IBOC Team SX 25.00 https://www.bikepedia.com/Quickbike/...spx?item=32493

IBOC Zero G 25.80 https://www.bikepedia.com/Quickbike/...spx?item=32494

Rockadile 25.80 https://www.bikepedia.com/Quickbike/...spx?item=32496
Novara




Ponderosa 26.00 https://www.bikepedia.com/Quickbike/...spx?item=32552

Team SL 25.00 https://www.bikepedia.com/Quickbike/...spx?item=32555
Voodoo




Bizango (orange) 24.30 https://www.bikepedia.com/Quickbike/...spx?item=38072

Leave the bottom bracket alone and just use spacers on the crankset.

Frim Bike Radar: "The Attain Pro is built around a 68mm BSA threaded bottom bracket"
If you put a MTB crankset on this bike, regardless of where you put spacers, you will screwup the chainline, which will screw up the shifting...

It's not just the BB width but also the additive factor of width of MTB cranks...
Use a road crankset... add a cassette which starts with larger cogs - Miche makes cassettes which start with 14 or 16 and 18 , in 9 speed for Shimano compatible shifting. (also have cassettes for Campy compatible). Miche makes great cassettes, Italian company, also available in US and most anywhere...
You might also be able to try a Gravel Crankset which goes lower (46/30) than common road of 48/32, if you don't like the road range...
Just get a cassette which can work with your desires.
Gravel Cranksets will be 2mm wider chainline for a 68mm BB, which would still work...

... mtb BB and crankset on a road bike... is a serious Kludge ...

You can get compact road cranks easily enough. Before these were availble, I used 110mm touring crankset with short BB spingle for perfect chainline. With 48/34t and 13-24t cassette. That was enough to get up any hills in Santa Barbara area. I recall there was extreme 20% grade short hill just past Summerland that I almost had to get off and walk!

you mean that 24mm diameter and 2,5mm wide? i found one on local web store

If you are using a hollow-spindle crank, or any one in which one or both arms clamp to the spindle, you've got to be careful about adding spacers that reduce the clamp length (unless there is "excess" spindle length, like a spindle designed for a 73mm BB and you mount it in a 68mm BB shell). I did that, added 4mm spacers on the crank side on my bike, and the left crank arm came loose. (Chainline also suffered, was dropping chains. Solution was to grind off small part of FD inner lip that was preventing the FD from going 4mm further in; Then assembled crank with no spacers as it should be, did not come loose again.)

I was going to say this as well.

Getting road shifters/FDs to work with MTB cranks has often been problematic. I believe road and mtb front shifter/derailleurs have different cable pull ratios from MTB in that gear range.

Might want to consider a road/gravel sub-compact crankset (46/30). Or a wider range cassette with either a 9speed Shimano MTB or 10 speed Shimano Road RD.

Yes a gravel 46/30 crankset sounds much more workable.

175 also sounds very long. How tall are you? I’m 190cm and use 172.5 cranks.

Also - your legs are not a fixed quantity for eternity. If you do more work, especially deliberately using lower cadence, hight torque at times, they will get less thin.

cyclezen The bikeradar quote - was that for the model year we’re talking about? Cube were definitely using pressfit BBs on all their road bikes up until 2017.

https://www.bikeradar.com/reviews/bi...ain-pro-review
The OP did say 2018 and said that 9 spd Sora was on t here - so OEM?
As far as I know Sora is only done in 'road' specs - so a confirm of 65mm BSA threaded BB?
even thought the Germans can get 'creative' with config's (some weird concept that they can 'do it better'... LOL! ) I would assume that if the frame is intended as basic/budget setuo, they would use the std config id the bike has a Sora group...
In any case, if there is a sora/shimano spindle crank on there, then replacing with a Shimano spindle crank (for road) seems the easiest/best option....
and care should be taken to NOT get a FSA lower end crank (adventure) which is NOT shimano spindle/BB compatible

If this site is accurate, it’s pressfit. Probably changed to T46 or some other threaded as per bikeradar in the years since then.
https://www.paulscycles.co.uk/bikes/...018-white__800

agreed on replacement strategy.

Ok, I see that reference in the description... so unless the BB is in bad shape, best then to use a crank with the same spindle diameter - which is prolly the std Shimano 24mm diameter...
Ride On
Yuri