Gravel Bike Gearing

[Roguemeister]

Also running 42 up front with 10-42 on the back.... Can't fault it for gravel, never felt like I needed something more on either end

[Grease_Monkey]

Don't discount the difference a 10-42t cassette makes compared to an 11-42t. You can run a 38t chainring with a 10-42t cassette and get the same top end as you can with a 42t chainring and a 11-42t cassette and a much lower granny.

 

Conversely if you are happy with a granny ratio of 42:42 then using a 10-42t cassette and a 42t chainring will give you massive top end.

[Pikey]

Don't discount the difference a 10-42t cassette makes compared to an 11-42t. You can run a 38t chainring with a 10-42t cassette and get the same top end as you can with a 42t chainring and a 11-42t cassette and a much lower granny.

Conversely if you are happy with a granny ratio of 42:42 then using a 10-42t cassette and a 42t chainring will give you massive top end.

i bought a 38t at time of building just haven’t used it yet . It was always a just in case back up plan....think if I was in hilly terrain it would of been used by now .

 

What is the top speed of a 38t & 10/42....when do you start spinning ,say 95/100rpm ?

[Jewbacca]

Don't discount the difference a 10-42t cassette makes compared to an 11-42t. You can run a 38t chainring with a 10-42t cassette and get the same top end as you can with a 42t chainring and a 11-42t cassette and a much lower granny.

 

Conversely if you are happy with a granny ratio of 42:42 then using a 10-42t cassette and a 42t chainring will give you massive top end.

As much as I agree, the cost implications of the initial install and subsequent cassettes isn't worth it IMHO.

 

As an 'ideal' setup then yes, that or the e-thirteen 9/46 would be amazing. I personally just can't justify spending 2500zar on a cassette when I can get one for 800 bucks.

 

But then I am stingy....

[Grease_Monkey]

i bought a 38t at time of building just haven’t used it yet . It was always a just in case back up plan....think if I was in hilly terrain it would of been used by now .

 

What is the top speed of a 38t & 10/42....when do you start spinning ,say 95/100rpm ?

 

So, for comparison's sake let's use a 700c wheel and 40mm tyre as a base, and only look at top speed at 80, 90, 100, and 110 cadence. I'll compare 42t and 38t chainrings:

 

1a. 42t chainring with 10-42t cassette gives you a top speed of 50,02km/hr at 90RPM. 

 

 

1b. 42t chainring with 11-42t cassette gives you a top speed of 45,49km/hr at 90RPM.

 

 

2a. 38t chainring with 10-42t cassette gives you a top speed of 45,25km/hr at 90RPM.

 

 

2b. 38t chainring with 11-42t cassette gives you a top speed of 41,09km/hr at 90RPM.

 

 

So you can see from this you get the same top end with a 38t chainring and 10-42t cassette as you would with a 42t chainring and 11-42t cassette. Obviously you get a much better granny with the 38t chainring. If you live in a non hilly area you can run a 42t chainring with 10-42t cassette and get extra top end without sacrificing low end. So IMO, if you need top end and low gears, the 10-42t cassette is worth the extra dosh and really makes 1x viable for road use without going for a super wide range cassette like that has massive jumps.

Edited April 21, 2020 by Grease_Monkey

[Grease_Monkey]

As much as I agree, the cost implications of the initial install and subsequent cassettes isn't worth it IMHO.

 

As an 'ideal' setup then yes, that or the e-thirteen 9/46 would be amazing. I personally just can't justify spending 2500zar on a cassette when I can get one for 800 bucks.

 

But then I am stingy....

 

Yeah I get that. I have had XD drivers on all the bikes I have bought new in the last while, so the cost isn't something I have really thought about until it came time to replace a cassette, then I want to cry.

 

When I built up my gravel bike recently though I went for a 38t chainring with an 11-42 cassette purely based on the cost of an XD setup. But the lack of top end doesn't bother me much purely because I ride on my own when I am on the gravel bike and I don't have to worry about hanging onto roadies. I am also not that fit, so I rarely get to a point where I need the top end. I do however regularly use the granny side,  so it's a sacrifice I am okay with.

 

For the guys that want the best of both worlds, XD and a cassette with a 10t cog is definitely the way to go though....

Edited April 21, 2020 by Grease_Monkey

[Pikey]

So, for comparison's sake let's use a 700c wheel and 40mm tyre as a base, and only look at top speed at 80, 90, 100, and 110 cadence. I'll compare 42t and 38t chainrings:

 

1a. 42t chainring with 10-42t cassette gives you a top speed of 50,02km/hr at 90RPM. 

 

1a.png

 

1b. 42t chainring with 11-42t cassette gives you a top speed of 45,49km/hr at 90RPM.

 

1b.png

 

2a. 38t chainring with 10-42t cassette gives you a top speed of 45,25km/hr at 90RPM.

 

2a.png

 

2b. 38t chainring with 11-42t cassette gives you a top speed of 41,09km/hr at 90RPM.

 

2b.png

 

So you can see from this you get the same top end with a 38t chainring and 10-42t cassette as you would with a 42t chainring and 11-42t cassette. Obviously you get a much better granny with the 38t chainring. If you live in a non hilly area you can run a 42t chainring with 10-42t cassette and get extra top end without sacrificing low end. So IMO, if you need top end and low gears, the 10-42t cassette is worth the extra dosh and really makes 1x viable for road use without going for a super wide range cassette like that has massive jumps.

That’s a cool comparison. Am surprised that the difference between the 10 & 11 Sprocket’s at the same cadence is nearly 5 kph ....

 

As mentioned by Jewbacca the E13 9/46 would be awesome with a 40 up front ....plenty top end and certainly enough granny . But for some reason have never been a fan of the E13 cassette with it’s proprietary tool. The jump in gears might also be a bit to big .

 

Also have enough 11 speed cassettes to get through ,maybe then I would consider other options. Might just unwrap that 38t after lockdown and be having me test ride in some hills ????

[pieterrossouw03]

What about running 44-17 on a gravel fixie?

2.4 times harder than my 39/28 and 11-36 on my mountain bike   

[Jewbacca]

What about running 44-17 on a gravel fixie?

2.4 times harder than my 39/28 and 11-36 on my mountain bike   

That would be about standard. 

 

I work on 3 to 1 fixie gearing. I am currently spare partsing a gravel bike fixie and was looking at running 39/15 or 39/16 so your gearing is pretty spot on with what I had in mind

[Spy007]

Quick question here and looking at all the comments.

 

have 42 front 11-42 back.

 

find in the hilly bits the 42 : 42 is a bit of a killer especially on the long climbs.

 

I am playing with the idea of a 34 in front???

 

Momsen 500 gp

 

ANd before i get lambasted. i am talking long climbs breedts, sterkies some mini munga rides etc.

 

top end is wearing thin and enjoy the cruise. due to lockdown weight gain and still recovering from Munga

[NickGM]

Quick question here and looking at all the comments.

 

have 42 front 11-42 back.

 

find in the hilly bits the 42 : 42 is a bit of a killer especially on the long climbs.

 

I am playing with the idea of a 34 in front???

 

Momsen 500 gp

 

ANd before i get lambasted. i am talking long climbs breedts, sterkies some mini munga rides etc.

 

top end is wearing thin and enjoy the cruise. due to lockdown weight gain and still recovering from Munga

 

Go for it. I was just looking at (well admiring, really) this build the other day:

https://bikepacking.com/bikes/logans-kona-sutra-ltd/

34 in front with 9-46 at the back is about as close to perfect for 1x gravel tourer IMO. 

 

You wont quite get the same range as the above build obviously, but all you really need to look at is how much top end speed you lose and how much that means to you. 

 

This will help:

http://bikecalc-staging.herokuapp.com/speed_at_cadence

 

At 90 RPM you currently get 45kph (assuming 700c wheels and 38mm tyres). That will drop to 36kph if you switch to 34t up front. That's not all that fast, so you'd miss it going downhill or with a tailwind. But I'd rather have happy knees.  

[gogo@]

My 2c for anyone still thinking about options...

I went for the Shimano GRX800 2x11 which gives 48x31 on the front and 11x34 at the back (theoretically expandable to at least 36 without any fixits added).

Proper it is too.  Don't write off the front derailleur too quickly.

This is very fast for gravel, yes, but the reason I have it is because it makes the tar bits that connect the gravel bits so much fun.  So the top speed is worth it.

It's a wider more friendly range but has no massive jumps, so pretty smooth, and I want/need it to do some nasty climbs too.

Plus-2 on good brakes - you'll need them 

[gogo@]

Quick question here and looking at all the comments.

 

have 42 front 11-42 back.

 

find in the hilly bits the 42 : 42 is a bit of a killer especially on the long climbs.

 

I am playing with the idea of a 34 in front???

 

Momsen 500 gp

 

ANd before i get lambasted. i am talking long climbs breedts, sterkies some mini munga rides etc.

 

top end is wearing thin and enjoy the cruise. due to lockdown weight gain and still recovering from Munga

Not sure about your set-up and tolerances but someone I know is stretching it with a 11-46 on the back and (apparently) getting away with it.  Anyone else tried that?

I would be loathe to drop some of the top speed...

[Tomik]

Quick question here and looking at all the comments.

 

have 42 front 11-42 back.

 

find in the hilly bits the 42 : 42 is a bit of a killer especially on the long climbs.

 

I am playing with the idea of a 34 in front???

 

Momsen 500 gp

 

ANd before i get lambasted. i am talking long climbs breedts, sterkies some mini munga rides etc.

 

top end is wearing thin and enjoy the cruise. due to lockdown weight gain and still recovering from Munga

 

You should only really need a 34t up front if you're carrying a load.

 

I just fitted a 40t chainring with a 10-42 cassette on my Stigmata and it's good enough for those long climbs without luggage. I'm reasonably fit.

 

You could also do it step-by-step: get a 38/40t ring first and if still not enough, get a 11-46 sunrace cassette. Or the other way around.

[ChunkyMonkey]

No,sold Fiona just before race to the sun last year, built the Niner RLT.

Think Fiona came 3rd as well

 

 

Did you see the photo I posted recently in “where has your bike taken you today “ of Fiona’s test ride?

That Niner looks strangely familiar...?

[ChunkyMonkey]

No,sold Fiona just before race to the sun last year, built the Niner RLT.

Think Fiona came 3rd as well

 

 

Did you see the photo I posted recently in “where has your bike taken you today “ of Fiona’s test ride?

That Niner looks strangely familiar...?