Building a Hardtail Frame

[kl3ggy]

Hey Guys,

Looking around at eventually upgrading frames. Something thats alittle more compatible with todays upcoming standards, while still being able to run my current parts. This got me thinking of custom building myself a new Hardtail frame. 140mm Travel, Fun Hardtail that can accept my current 26" Parts but also accept 27.5" wheels at a later date.

Specs that im leaning towards so far:


Measurements based off of 27.5" 140mm Pikes, Axle to Crown length of 542mm.

Material: 4130 Chromoly
Chainstay Length: 419mm
Bottom Bracket: Threaded
Bottom Bracket Height: 321mm
Head tube Angle: 67.5
Seat Tube Diameter: 30.9mm
Internal Cable Routing

Still trying to figure out what Reach and ETT that im wanting. Thinking of just basing it off of a 2016 Large Santa Cruz Chameleon.

What are some must have features that you would like to see, given the chance to build your own?

 

[link1896]

Good tyre clearance for big 27.5" tyres. Nothing shits me like gravel getting stuck in the tread fouling on frame.
post mount for caliper that's big enough (and strong enough) for your chosen rotor size without adapters

 

[spoozbucket]

I'll be going for a custom frame again next year, same geo as the last failed build.

What sort of riding will you be doing on it, more Enduro/DH or just trail riding?

Why would you want internal cable routing on a nice simple HT? I get it for the dropper post but that's the only reason I can think of, the last thing you want is more water entry points in a steel frame. My current frame was supposedly ED coated before powder coating and it still has rusty water coming out of the breather hole thingies after a wet ride.

I am on a 67deg HA now and find it far too steep to have any serious fun on.

Is the BB height with 650b wheels? My current 650b HT frame had a BB height of 300 with 26" wheels on it, was loads of fun but loved smacking rocks.

 

[wkkie]

Some of the features I would go with are 12mm rear end, threaded bottom bracket, tapered headtube. Even if you have a straight steerer fork now you can use a crown race reducer and not limit your choices when you look to upgrade the fork.

Internal routing always looks good. And make sure you can fit a dropper.

 

[JTmofo]

Our of interest, where do you get the frames made?

 

[kl3ggy]

I'll be going for a custom frame again next year, same geo as the last failed build.

What sort of riding will you be doing on it, more Enduro/DH or just trail riding.

Why would you want internal cable routing on a nice simple HT? I get it for the dropper post but that's the only reason I can think of, the last thing you want is more water entry points in a steel frame. My current frame was supposedly ED coated before powder coating and it still has rusty water coming out of the breather hole thingies after a wet ride.

I am on a 67deg HA now and find it far too steep to have any serious fun on.

Is the BB height with 650b wheels? My current 650b HT frame had a BB height of 300 with 26" wheels on it, was loads of fun but loved smacking rocks.

Currently loving the feel of the 2010 Santa Cruz Chameleon. Since I sold the Dually. Would love a do it all bike.

Currently the HT is 68deg HA. Would love to go slacker, but not to slack. I have a lot of hills around in Brisbane so playful while descending but can go back up is key. Don't mind sacrificing the climbing ability little.

One thing that I would definitely like would be a little more room up front then what I currently have with the 50mm Stem. This is where i come little unstuck. I can see the Geo for my current frame, but i don't know what to change to give me that little more room without throwing off the rest of the geo.

About the Internal Routing..... Now that you mention it I guess it makes sense. I love the clean look of not having cables all over a nice frame.

Our of interest, where do you get the frames made?

I have a mate who is a Engineer, Steel Fixer, Plastic Injection Moulding do anything type of guy, who has all the lathes, welders, benders I imagine i could need.

 

[spoozbucket]

I have a mate who is a Engineer, Steel Fixer, Plastic Injection Moulding do anything type of guy, who has all the lathes, welders, benders I imagine i could need.

That is a pretty awesome friend to have!

A slack headangle won't make a bike climb poorly, reach, rear stays and seat angle(most important IMO) will have much more effect. If you get the geo right you will have decent weight on the front wheel on climbs which will let you get away with running a slacker HA.

 

[kl3ggy]

A slack headangle won't make a bike climb poorly, reach, rear stays and seat angle(most important IMO) will have much more effect. If you get the geo right you will have decent weight on the front wheel on climbs which will let you get away with running a slacker HA.

This! Without building prototypes and riding them, how do I work that out?

The Stanton Switchback seems to have one the slacker HT angles that I've seen but I don't know how it would climb.

SWITCHBACK GEOMETRY

SWITCHBACK 16.5" 18"
1. Stack (mm) 615 624.5
2. Reach (mm) 395 410.5
3. Virtual Top Tube (mm) 587.5 608
4. Actual Top Tube (mm) 562.5 578
5. Seat Tube Length (mm) 419 457
6. Chainstay Length (mm) 415 415
7. Wheelbase (mm) 1074 1094.5
8. Bottom Bracket Drop (mm) 43 43
9. Head Tube Length (mm) 110 120
10. Head Tube Angle 65˚ 65˚
11. Seat tube Angle 72˚ 72˚
12. Axle to crown height used for above measurements (mm) 510 510

 

[spoozbucket]

Hmmm, weird double post, sooooo.

This was my last custom frame, I think I put this up in the AM thread or somewhere.
I am 182cm tall and pretty fat so I need to sit further forward than a lighter person at the same height, trying to move a fatty up a hill without lifting the front is pretty difficult on older geo hardtails.

My next frame will be almost the same as above but the rech would be wound out to 455 and the HA slackened to 64.

EDIT- That was modelled around 2Souls sliding droputs but they suck the D and I will never have sliding dropouts again, back end would be 420mm.

 

[kl3ggy]

Hmmm, weird double post, sooooo.

This was my last custom frame, I think I put this up in the AM thread or somewhere.
I am 182cm tall and pretty fat so I need to sit further forward than a lighter person at the same height, trying to move a fatty up a hill without lifting the front is pretty difficult on older geo hardtails.

My next frame will be almost the same as above but the rech would be wound out to 455 and the HA slackened to 64.

EDIT- That was modelled around 2Souls sliding droputs but they suck the D and I will never have sliding dropouts again, back end would be 420mm.

Awesome. Thanks for posting! I am 187cm and about 99kg before riding gear

 

[spoozbucket]

Yeah I'd say you'd want a similar sort of seat angle, a couple of companies are finally steepening the seat tube angle for larger frames. If you look at an XL AM hardtail frame a lot will still have a low 70's STA. Find a good side on pic and throw in in to trusty old paintbrush and draw a vertical line down from the middle of the seat to see where most of your weight will sit.

The further back you sit the more time you spend in hunched XC mode, it also makes climbing in the low ratios difficult as you get so much torque to the ground with almost no weight on the pedals which makes the front wander in switchies, especially if it is rooty.

Frame with a slack seat angle, not the best pic I know but I wanted two 650b frames-

View attachment 322576


Nice steep 75deg STA(static unlike the Cotic which is a sagged STA+ so it would be more like 70 without sag[and there is no sag when climbing])

EDIT- The Last is a 650+/29er but the stays can be 2mm shorter than the Cotic

Double Edit Don't take what I say as gospel, it is just my opinion and others disagree, different people like different things.

Hmmm, why can't delete the bottom pic?