---HELP NEEDED ---Turning a MTB into a road bike---

lawrencecatania

Hi all

I have just bought a Cannondale Trail SL2 for commuting and fitness purposes.
On my first ride i noticed how awful are the gear ratios. They are way too low. I resembled a hamster trying to generate electricity :?

Presently it is equipped as follows:

Rear 11-36 cassette
Front 42/32/24
I am planning to change the front crankset with a Shimano 105 (50/39/30)

Do you guys think it's a good combination or there might be a more reasonable solution?

I appreciate you suggestions

Regards

nicklouse

there is a very very small chance that it will fit as the rings will catch the chain stays.

and at a cadence of say 90 you will be doing about 30mph

and then there is the rest of the parts that may or may nor need changing.

getting_on_a_bit

I converted an old steel kona to a commuter,simply replaced the triple with a single 46t ring and kept the rear cassette.Doesn't like the chain line at the biggest rear cog otherwise been fine for many years.Changed the tyres to slick 1.6" fatboys and flies along.

markhewitt1978

42/11 is the same as 50/13. The top gear on this bike at a ratio of 3.8 isn't much lower than on my bike with a ratio of 50/12 = 4.16. And I only need to use a gear that high when I'm maxxed out going down a steep hill.

So either the OP has a power output to rival Chris Froome, he's in the wrong gear in the first place, or something else I can't figure out, but the bikes gears don't seem too low to me, especially as it's a MTB.

PS. You don't turn a MTB into a road bike just with higher gears!

The Rookie

I suspect Lawrence that you need to learn to spin at circa 100rpm, not grind at 50rpm, yes it does feel too fast until you get used to it.

I run a 46T 1x9 and only use the top 3 gears on the cassette when I'm running over 30mph downhill (hitting 40mph on one section of my commute).

Rings will almost certainly catch the chainstays (wider on an MTB for the wider rear tyre and axle).

Put some slicks on it, learn to pedal at the right cadence and then start tweaking it to suite you/your commute.

gbsahne001

my hybrid runs the same chainset with a 12-27 cassette and it holds it's own at 18 - 20mph, even with 700 x 38 tyres fitted and like others rarely use the top 2 gears

keef66

I contemplated turning my light, rigid MTB into a road bike.

Big jumps between gears, wrong frame geometry and limited hand positions on the bars were all driving me to distraction

Got as far as putting slicks on it and gave up. Would've cost a fortune and still not been any good. I bought a road bike.

samsbike

keef66 wrote:

I contemplated turning my light, rigid MTB into a road bike.

Big jumps between gears, wrong frame geometry and limited hand positions on the bars were all driving me to distraction

Got as far as putting slicks on it and gave up. Would've cost a fortune and still not been any good. I bought a road bike.

+1 still cant figure out what to do with the mtb

bikaholic

keef66 wrote:

I contemplated turning my light, rigid MTB into a road bike.

Big jumps between gears, wrong frame geometry and limited hand positions on the bars were all driving me to distraction

Got as far as putting slicks on it and gave up. Would've cost a fortune and still not been any good. I bought a road bike.

This is what is so disappointing about this thread and about BR in general - you don't try things out and follow things through.






I've built about about 30 of these, that is, converted MTBs to dropbar bikes, some hardtails, some full sussers.

Nurture the OP's desire to modify his bike and we might get to see his build process. You will learn a lot from the mistakes as well as the successes along the way.

gozzy

Why would anyone want a full suspension drop bar bike?

The Rookie

A desire for something different rather than something better!

Initialised

bikaholic wrote:

keef66 wrote:

I contemplated turning my light, rigid MTB into a road bike.

Big jumps between gears, wrong frame geometry and limited hand positions on the bars were all driving me to distraction

Got as far as putting slicks on it and gave up. Would've cost a fortune and still not been any good. I bought a road bike.

This is what is so disappointing about this thread and about BR in general - you don't try things out and follow things through.






I've built about about 30 of these, that is, converted MTBs to dropbar bikes, some hardtails, some full sussers.

Nurture the OP's desire to modify his bike and we might get to see his build process. You will learn a lot from the mistakes as well as the successes along the way.

Now I know what to do with the bars, brakes and shifters when I get around to re-doing the front end of my road bike. Want's deeper bar, longer, lower stem, hydraulics and a better groupset.

How do hardtails with drops handle road descending, I'm thinking it'll be faster than a rigid bike on 25mms especially on rough surfaces?

Back on topic.

I've run a few gear combos on converted MTBs latest experiment is 44/36/22 x 11-32, the steps on the front feel wrong, 46/34/22 sounds better. The best I've tried so far seems to be 48/36/26 x 11-28. To big a range at the front and the chains too long or rubs the bottom of the derailer. I think 48/36/24 x 11-25 would feel pretty good, plenty of range on the rings and nice close ratios on the cassette.

gozzy

The Rookie wrote:

A desire for something different rather than something better!

I more meant, what practical reasons are there for adding drop bars to a mountain bike?

Does the "something different" equate to a decent and rideable bike, as the shift of centre of gravity of the mountain bike frame coupled with the ride position of drops is going to affect the ride. I dare say there's some other factors to take into account as well.

So, is it good different, or bloody awful different? What're the benefits?

Initialised

Gozzy wrote:

The Rookie wrote:

A desire for something different rather than something better!

I more meant, what practical reasons are there for adding drop bars to a mountain bike?

Does the "something different" equate to a decent and rideable bike, as the shift of centre of gravity of the mountain bike frame coupled with the ride position of drops is going to affect the ride. I dare say there's some other factors to take into account as well.

So, is it good different, or bloody awful different? What're the benefits?

Not that I'm that into mechanics and damping and that but I think suspension on a road bike (or drops on an MTB) would be amazingly fast on descents on rough road surfaces that would challenge the nerve of a roadie.

MichaelW

Your existing front mech may not play well with a 105, 30/40/50 chainset. Road mechs are incompatible with MTB shifters.
Road rings may not be compatible with chainstay profile. Check the bottom bracket compatibility.
Mixing road and MTB components is a minefield. Touring cyclists know to tread with care and the experts on merging these 2 systems are probably on the CTC forum.

desweller

You might have more luck hunting up a touring triple (e.g. 48/38/28) to clear the chainstay, rather than a road-specific item. If you go for a square taper chainset then you also have the option of pushing the chainrings out a bit by using a longer crankshaft than the recommended one, at the cost of compromising chainline.

You'll have a job getting gears as tall as a road bike though, with 26" wheels.

itboffin

It's been done before



and i have a version sitting in Paddington station since Feb this year, it handles like a car with two flat tyres riding down an ice covered mountain road.

desweller

itboffin wrote:

It's been done before



and i have a version sitting in Paddington station since Feb this year, it handles like a car with two flat tyres riding down an ice covered mountain road.

That sounds like fun actually.

Initialised

DesWeller wrote:

itboffin wrote:

It's been done before



and i have a version sitting in Paddington station since Feb this year, it handles like a car with two flat tyres riding down an ice covered mountain road.

That sounds like fun actually.

Slap on some ice tyres and it's the perfect Winter commuter.

rolf_f

Initialised wrote:

DesWeller wrote:

itboffin wrote:

It's been done before



and i have a version sitting in Paddington station since Feb this year, it handles like a car with two flat tyres riding down an ice covered mountain road.

That sounds like fun actually.

Slap on some ice tyres and it's the perfect Winter commuter.

To fit ice tyres on that you'd need to go back to 26inch wheels - and then it is just an MTB with road bike gears and pointless suspension (cos you don't need suspension in winter if you don't need it in summer!). I do approve of this Bianchi in terms of mad aesthetics though! You'd suspect the owner to be a lot cleverer than you but you wouldn't know why! Either that or he'd just been released from the local asylum with a tool kit and an Ebay account

desweller

Rolf F wrote:

Initialised wrote:

DesWeller wrote:

itboffin wrote:

It's been done before



and i have a version sitting in Paddington station since Feb this year, it handles like a car with two flat tyres riding down an ice covered mountain road.

That sounds like fun actually.

Slap on some ice tyres and it's the perfect Winter commuter.

To fit ice tyres on that you'd need to go back to 26inch wheels - and then it is just an MTB with road bike gears and pointless suspension (cos you don't need suspension in winter if you don't need it in summer!). I do approve of this Bianchi in terms of mad aesthetics though! You'd suspect the owner to be a lot cleverer than you but you wouldn't know why! Either that or he'd just been released from the local asylum with a tool kit and an Ebay account

Why?