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MTB hardtail to flat bar gravel conversion - is an older geom better than newer LLS?

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[#13536614]

Hello Forum,

I’m looking to buy / build a flat bar gravel bike. Thinking of buying a XC hardtail mountain bike and putting some rigid forks on it. 

Wondering if an older geometry frame is more suitable for this use or a newer frame with long low slack geometry works just as well?

Aim is to ride the bike on mix of road (30%) and off road (70%) on easy not technical terrain and maybe use for a bit of commuting.

I’ve got a 2017 GT Grade and have never really got on with it. The drop bars feel too far away so I never really use them but then bumpy or twisty sections feel crap on the hoods.  Mud clearance is also terrible, I currently have 33mm tyres and the sidewalls are constantly getting full of mud and scraping the chain stays and getting stuck. I looked into downsizing to 650B wheels but it’s the sidewalls that are the constraint so that didn’t help. 

I don’t really need any more bike, I think it’s fine for the type of riding I want for it. Just think I prefer flat bars and more mud clearance. 

I’m also not trying to set any records just make it more enjoyable to ride out the doorstep and use the easy bridleways and quiet country roads nearby.  And get some more time on a bike a work off the belly fat more.

Hence thinking an older XC hardtail with rigid forks might be the type of gravel bike for me. 


 
Posted : 09/08/2026 11:16 am
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Why not just buy a flat bar gravel bike?

Something like the Sonder Camino Flat Bar?


 
Posted : 09/08/2026 11:45 am
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What they said. 

Plenty of "almost a mountain bike" gravel bikes out there with long enough reach to suit putting on flat bars. Eg...

https://www.cotic.co.uk/product/flatbarcascade


 
Posted : 09/08/2026 11:51 am
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Maybe just look for a carbon forked On One Whippet? Pretty much what you want and shouldn't be expensive. I'd probably go for the more XC side of things rather than lls.


 
Posted : 09/08/2026 12:12 pm
 Bazz
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I've recently retired my circa 2012 On One Scandal and for some reason I just can't bring myself to sell it, probably because it wouldn't really be worth enough to make it worthwhile, but I do keep thinking that with the geometry it would make a decent flat bar gravel bike.


 
Posted : 09/08/2026 7:18 pm
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Looking on eBay / STW classifieds because of low budget constraints.

Im hoping I can get better value for money buying 2nd hand and using spares parts I all ready have lying about. 

Any advice on whether an older xc bike from 2018 would have better geometry for this usage compared to something a bit newer with a more slack head angle? 

 


 
Posted : 09/08/2026 9:09 pm
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Local recykabike place might work well. 

 


 
Posted : 09/08/2026 10:31 pm
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Sounds like a Marin DSX or Kona Dew or Croix de Fer flat bar are ideal... 


 
Posted : 09/08/2026 10:36 pm
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My two bikes both fill your brief perfectly in slightly different ways.

A 26" monstercross built up around an old Rockhopper frame I bought off here for £25 (I ran it for two years as a rigid MTB but prefer it in its current drop bar guise).

A 29" Sonder Frontier based on a frame bought new from their eBay outlet last year for £159.

So, buy second hand, and/or keep an eye on this eBay store.

EDIT: I prefer the slightly old skool geometry of the Frontier to the V.3 Inbred it replaced for my (effectively your) purposes. 


 
Posted : 09/08/2026 10:55 pm
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It's a yes from me. My 2016 Highball is my gravel bike now, it's been on 2.2 Race Kings for years which the gravellers are finally catching up on. Esp. 70% off road flat bars is definitely where you want to be. Shifters and brake levers are cheaper too.


 
Posted : 09/08/2026 11:05 pm
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I’m using a 26” 2007? Kona Steely, it’ll take a 29 wheel with big tyre in the rigid fork, a 2.3 27.5 Maxxis minion SS will squeeze in the back.

It’ll just about fit a 29 rear wheel with a cx tyre on too.

It rides best with 27.5 26 mullet.

i tend to use 27.5 all round due to an abundance of tyres in the pile.

Everything on it is fairly high end but old standards, so cheap or free.

It’s not the fastest or lightest but its ideal for local  rides/shopping or easy trail centres. 


 
Posted : 10/08/2026 9:48 am
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I have a 2015 scott scale that I've made into a fast flat bar gravel bike, with a set of Pipedream Sirius rigid forks. Thought about carbon forks, to better match the aesthetic, but haven't yet. It's very rapid, it's very direct, it's also not getting much use either, as my hardtail does the same job.

The only riding I think I'd use it for now is mixing up some light trails with back lanes, which is few and far between. so if anyone is looking for one, and can fit an XL scale....

 


 
Posted : 10/08/2026 10:30 am
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Answering the OP, yes, no, maybe.

I'm still riding a lightweight 2005-ish XC bike. On slicks. Bike fit is only slightly more upright than my road bike.

Coincidentally it also used to have pipedream rigid forks, but they weigh a ton for what they are; I swapped them for some 4" air forks that weigh (nearly) the same and have a lock-off for tarmac / gravel.

 


 
Posted : 10/08/2026 11:39 am
lovewookie reacted
 jfab
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A colleague of mine had a similar age GT Grade and found the same, it's now been relegated to a winter road bike instead for commuting and he's built up a couple of older hardtails into flat bar and drop bar gravel contraptions. He's generally found if going drop bars on a hardtail (with or without suspension forks) that going older XC geometry works better with the shorter reach. If going flat bars, it's less of an issue really and probably more about just getting the right bars and stem to suit the geo of the frame you end up with.

Personally I'd go for whichever 29er XC Hardtail frame/bike was local and cheap. Scott Scales seem to be widely available for not much money second hand, some of the cheaper stock builds have really heavy forks/kit though and the second hand values don't always tally with how high the model was in the range when new. That means you can get an absolute bargain if the seller doesn't realise they've got a high spec one, or vice versa.


 
Posted : 10/08/2026 12:37 pm
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Actually it occurs I didn’t answer the specific question. I’m not sure the geometry really matters (as long as it isn’t terrible) if you’re not changing the bar/stem type much. 
The only real advantage of an older frame is cheapness and a good use of perfectly good obsolete parts.

The only issue I can see  is decent rigid forks with the correct length to keep the numbers ball park, without paying more than for a Nice used  light suspension fork. 


 
Posted : 10/08/2026 2:11 pm
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Posted by: jamesoz

The only real advantage of an older frame is cheapness and a good use of perfectly good obsolete parts.

There are a bazillion old frames out there for little money. I guess the value in this proposition is whether you like a project or not. And whether you have a bunch of the bits needed already, especially fork and drivetrain.

If I was going to have to buy a whole bike's worth of bits to make an old frame into a complete bike... might as well buy a complete bike...


 
Posted : 10/08/2026 4:13 pm
 IHN
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This is a good watch on this subject...

We Took Vintage Mountain Bikes On An Epic Gravel Ride


 
Posted : 10/08/2026 4:21 pm
 PJay
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If you're not put off by the weight penalty of steel I can thoroughly recommend a Singular Swift frame & forks. The tricky bit is likely going to be finding someone willing to part with one.


 
Posted : 10/08/2026 5:45 pm
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Thank you folks for the responses it's been very helpful.

I don't want to spend loads as I'm not sure if I don't like gravel riding or I just don't like it on the bike I have at the moment.  I like the idea of gravel riding and thats what I have on my doorstep.  

I'm happy to take on a semi-project, I have a few bits and bobs for spares and happy to replace a old suspension fork with a rigid fork but really I'm looking for something thats pretty much ready to ride.  Anything requiring more effort then I'm more inclined to getting a new bike that works straight out the box.

Good to hear the older bikes are very much suited to this kind of riding and newer ones will work fine.  I won't sweat over the geom figures too much as long as the bike fits.

Regarding material, I had a 853 hardtail many moons ago, it was lovely but weighted a ton.  I think I prefer the lighter weight of an Alu alloy frame for me unless I happen to find a mega bargain carbon frame.

 


 
Posted : 10/08/2026 6:22 pm
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I have a couple of Grades from back when they first came out. Tyre clearance was always a problem, so in the end I used one as my winter road bike, and the other has been converted to flat bars, which I use for commuting.

I have an original 26-inch Scandal with the On-One carbon fork. I’ve had a set of 650b wheels on it, and it had room for 2.00-inch tyres. I really liked that setup. It was fast and light, but more robust than a gravel bike, with that chunky fork. It’s currently back on 26-inch wheels with Ice Spikers, so I always have a bike set up and ready to ride on ice, although there isn’t much of it around at the moment.

My wife has two On-One Free Rangers, both converted to flat bars, one for road riding and one for gravel. I find the flat-bar gravel bike a little twitchy when things get steep compared with my drop-bar Camino and Pickenflick. If I were to use a gravel frame, I’d look for something with geometry more like the Camino.

If you’re using a modern bike, you may need flat-mount callipers, especially at the rear. We couldn’t fit an adapter at the back. We managed to fit one at the front, but it looks rubbish, so if I were doing it again, I’d use flat-mount brakes at both ends.

If I were converting an old bike, I’d probably look for a mid-2000s Kona Caldera or Kula, from when they still had the round tubes. The Kula was the bike that got me back into mountain biking.

I was chatting to a Dirty Reviver who had done a drop-bar conversion on his late-’80s Rockhopper, which he’d owned from new. I thought it looked great, although that might partly be because I’d lusted after one when I was a kid.

 
 
 
    

 
Posted : 10/08/2026 6:55 pm
 FOG
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I have a SolarisMax, the last of the old headbadge model. At the moment it has carbon forks and gravel tyres on narrowish wheels and it makes an excellent gravel bike for my needs. At other times it has suspension forks and bigger wheels and tyres. As somebody has already said geometry is fairly irrelevant, it works well in either set up. My only cost were the carbon forks, everything else came from the spares box


 
Posted : 12/08/2026 10:04 am
kelvin reacted
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Posted by: Bazz


I've recently retired my circa 2012 On One Scandal and for some reason I just can't bring myself to sell it, probably because it wouldn't really be worth enough to make it worthwhile, but I do keep thinking that with the geometry it would make a decent flat bar gravel bike.

14376018696_b2061f25aa_o.jpg

 

My even older Scandal made a very decent gravel bike.

 


 
Posted : 12/08/2026 10:43 pm
hardtailonly reacted
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Posted by: jairaj

Thank you folks for the responses it's been very helpful.

I don't want to spend loads as I'm not sure if I don't like gravel riding or I just don't like it on the bike I have at the moment.  I like the idea of gravel riding and thats what I have on my doorstep.  

I'm happy to take on a semi-project, I have a few bits and bobs for spares and happy to replace a old suspension fork with a rigid fork but really I'm looking for something thats pretty much ready to ride.  Anything requiring more effort then I'm more inclined to getting a new bike that works straight out the box.

Good to hear the older bikes are very much suited to this kind of riding and newer ones will work fine.  I won't sweat over the geom figures too much as long as the bike fits.

Regarding material, I had a 853 hardtail many moons ago, it was lovely but weighted a ton.  I think I prefer the lighter weight of an Alu alloy frame for me unless I happen to find a mega bargain carbon frame.

 

I’ve always used hard tails for gravel riding.  From a 2015 carbon Highball, a 853 Cotic, a titanium HT and now a 2021 carbon Highball.

The frame materials have made no real difference to the ride- tyres and forks are where it matters IMO.

 


 
Posted : 13/08/2026 5:26 am
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Posted by: FOG

As somebody has already said geometry is fairly irrelevant,

Small differences in geometry are massively overhyped.

 


 
Posted : 14/08/2026 9:38 am