ta111

Hey fellow riders,

I've been thoroughly enjoying my 2020 Grand Canyon AL 6.0 MTB, but lately, I've been using it more for fitness rides on roads and gravel paths. To optimize it for speed, I'm planning some modifications and would love your input.

First up, I'm looking to swap out the tires to ones better suited for faster surfaces. (probably Continental Race King)

Secondly, I'm considering upgrading the crankset to support higher speeds. Currently, I've got the SHIMANO DEORE XT HOLLOWTECH II MTB Crankset 2x11-speed with a 36-26 chainring setup. My idea is to replace the larger 36-tooth chainring with a 38-tooth one while keeping the smaller 26-tooth for those challenging uphill sections.

Has anyone tried a similar modification? Will the 38-tooth chainring work well with the 26-tooth one, or am I better off considering a different setup?

I'd greatly appreciate any insights or experiences you can share on this topic. Thanks in advance for your help!

soyabean

Even if you can lock the front suspension, it helps, but the geometry is still all wrong compared to a good urban bike.

And if you can't lock the front suspension, there's no point. Get another bike.

Don't get me wrong. the Canyon is a nice bike, but Marathons on that just won't work.

delbiker1 

If you want to do a lot of the road/gravel riding, an appropriate bike would be much better suited to doing that. You surely can do it with what you have, but you will never get the same performance, handling and comfort. Going from a 36t to a 38t ring is going to make almost no difference on it's own. A jump of 6 tooth would definitely give you more speed. Many set ups have 42 tooth front with wide range cassettes. If your front dr can handle the 42 tooth, it will need to be raised a bit and cable adjusted, then you would just need to switch to a longer chain. If you are using a cassette with the small cog of 10 or 11, not much you can do there. I had 42 front with 11-36 rear for a while, the only time I spun out in 42-11 was going downhill. I believe that gives about 28 mph at 100 rpm pedal stroke.

In the end, my opinion, if you can afford it, and your going to use it quite a bit, get a different bike. If you can do the work on the bike and want to keep the cost down, there are a slew of very nice road/hybrid/gravel bikes available. Or, an older hard tail mountain bike, like a stumpjumper/rockhopper, that make for very nice conversion gravel/road bikes. That might involve more work and dollars, but can have fine results. Once again, if you can afford it, get the right style of bike. If not, make do with what you can.

Front suspension for the road/gravel is a real detriment, a lot of extra weight, bad handling, even if you can lock it.

veganbikes

Agreed with others just get a bike more suited to your current riding. Have multiple bikes is a good thing. It is quite hard to have one bike that can do everything well it will do some things well and others not so well. I would rather have a mountain bike for mountain biking and a road or gravel bike for the rides you are looking to do.

I could go through the trouble of swapping out the front fork to a suspension corrected carbon fork and maybe be able to fit a larger chainring and put on different tires and all of that but when I want to mountain bike I would undo all of that and it is more trouble than it is worth and the bike still won't be a great bicycle for the road.

Andrew R Stewart 

Having watched many (as in many dozens) of customers go through this process of changing use and expectations I find that most will not be satisfied with the changes of gearing the OP asks about. An aprox 5% increase of ratio is very small (that's about half the 10ish% that many consider a good difference between adjacent ratios). And unless one also increases their power by that amount the body will still run out of ability at only slightly higher speed, at best.

The classic method to go faster that is body related is to learn how to pedal faster, as in cadence. Does the OP know their comfortable cadence range when on a flat surface? It is harder to train the body then to buy parts though that is why those who have a need (paycheck? ego among clubies?) spend so much time putting in the work on their pedaling.

Now a lighter tire with less tread WILL make a difference. Less so in top end speed and more so in the bike's feel or reaction to inputs. The bike feels more lively and accelerates easier. For me these are greater aspects then top speed is IME.

I completely agree that body positioning will also make a significant difference. The more of the body that can be applied to going forward the more speed is potentially available. Bikes made for control over rough surfaces tend to have a more upright body position and wider/open spread between the hands (wider bars). Both increase the aero drag and the faster one goes the greater the aero drag is what one is held back by.

When I use to work the sales floor I would use auto references to help explain this stuff. Trying to go fast on smoother surfaces with a MtB is like driving a pick up truck on the road. When alone it's fine but when compared to other road users the qualities that work on dirt are limiting when compared to a sports coup, let alone a true sports car. (Just as that sports car suffers off road were one to try).

So as long as the OP rides by themselves most all the time and isn't competitive when with others (or pretending they are racing when they see another rider) doing what is proposed will be fine, till it isn't.

As to the ft der handling the added 2 teeth difference- likely it will and likely there might be a tad more shifting sluggishness or effort. Enough to mater for the OP's skill at shifting and ability to adjust/tune the der (which will be needed) I don't know. Andy (who is sensitive enough to all this to end up with more than just one bike in his life)

grumpus

ITYF yours is a 2019, the 2020 was 1x.
I don't think you'll notice a difference* between 36 and 38 teeth, and shifting may suffer because chainrings are designed as matched sets - the ramps and cutaways may not line up. I'd be looking at 40 or 42 teeth for a noticeable improvement, or you could just train for faster pedaling. You should fit a longer chain if you fit a larger ring - you must be able to run the largest sprocket amd the big ring without locking up the derailleurs or breaking the chain.

If you haven't already gone tubeless, that can be worth a few watts regardless of the tyre.


* 36 to 38 is 5.6% while 11 to 12 is 9%

Duragrouch

As I said on the other duplicate thread:
Thanks. OK let's unpack this.
Delta 31 teeth in back plus delta 10 teeth in front equals 41 teeth capacity needed for rear derailleur.
M8000-GS says 39 teeth total capacity (a surprise, my measly Shimano Tourney TX GS $13 RD has 45T capacity). So you are currently very marginal for the rear derailleur in terms of enlarging your gear range, front or rear. M8000-GS also says max front difference 10T, which you have.

Your current gear range is 17.9 to 94.7 gear inches. That's a great low, I don't think you need lower unless off-road on super-steep uphills; For a road bike, 17.9 is usually plenty low. 94.7 is also a good high, but if you want higher, what you need is a bigger front chainring, and 16T front difference is super common these days, that would give you a 42T chainring high. Plugging that revision into gear calc yields a 110.5 gear inch high, with excellent numbers through the range with a lot less overlap and duplicate gears. That's not a 120 race-high, but still pretty fast. That will bump your needed rear derailleur capacity to 47 teeth. A typical GS rear derailleur is rated for 45 and usually conservative, you could probably get away with that with a GS (mid) cage length (and preferrable for ground clearance) but if not enough capacity, a long cage should definitely work. However your front derailleur is only rated for 34-38T and 10T difference. So...

To get that higher gear range, you need:
- 42T large/high chainring
- front derailleur that can handle 42/26 (and pictures show your current FD to be one of those newer weird mounts, not road or band-clamp style, so you may need new FD to be same)
- rear derailleur that can handle 47T total capacity
- longer chain

Alternate option: Change the cassette to 10-42, that gives you 104.2 gear inch high, not as high, and you might need a different freehub body to accept a 10T small cog, not certain.

I'm not the authority on specific parts, others here are good at that, I encourage them to chime in.

70sSanO

As others have said, making the conversion might not get you what you want. The other part is cost.

Ideally you would want to swap out the suspension fork for a rigid. There “might” be some possibilities to minimal handling improvement if you get the best ATC and offset to quicken things up, but you would want someone with real framebuilding knowledge to give you guidance.

Ultimately you might want to get dirt drop bars, which opens up more cost.

You could end up with a cool mod or a frankenbike that completely misses the mark.

John

Trakhak

Back when I was commuting on my Cannondale mountain bike, all I did to increase my speed was install slick tires and bolt-on time trial/triathlon/aero bars. I didn't bother with changing the drive train. As noted above, if your cadence range is sufficient, you'll be able to get pretty close to road bike speed with such a setup without changing your gearing.

Duragrouch

The gearing changes noted are not that expensive. However, it's still money, and best to look before you leap. I did plenty of calculations before my own conversion from 1X to 2X on a folder, and the results were exactly as planned. But for factors that cannot be changed such as frame and fork geometry, sounds like it would be good to sample some bikes that might be more ideal in that respect. But that's a lot more money, unless you get a good trade-in or sale price on your current bike. It's truly astonishing these days, the parts available to make minor adjustments in bike fit, if the frame is generally the correct size; I have a one-size-fits-all *folder*, supposed to fit between 4'8" and 6'3" height, the diverging angles of the handlebar riser/stem and the seatpost to increase the effecting top tube length as both go up, helps a lot. But other adjustments in seat position, handlebars, aero bars (and I need spacers to raise those with respect to the handlebars), have resulted in a really good fitting bike for me. Try out other bikes, if one feels better, take measurements and notes on difference in geometry versus your current bike; Once the seat is adjusted for you in height and fore/aft (with respect to bottom bracket center), what is the horizontal distance between the seat and handlebars, what is the height difference between the two, etc. Because I would think fit comes foremost in importance.