Guide
Getting a frame that fits
Start here
Your current bike is the best guide
If you have a bike you like, its numbers tell me more than any size chart. Look up your size on the maker's geometry page and write down the reach and stack, plus head angle, seat angle, chainstay length and BB drop if they're listed.
Only have top tube length and seat angle? That's fine, I can work reach out from those. Then ask yourself what you'd change. A bit longer? Higher at the front? Roomier tyres? That's the brief.
In the designer, the Compare my bike tab draws your bike over the new frame and lists the differences.
Watch: comparing your bike (13 seconds)
The two big numbers
Reach and stack
Reach
How far forward the top of the head tube is from the bottom bracket. It decides how stretched out you feel. Cramped means more reach, reaching for the bars means less. 10 mm of reach is about the same as 10 mm of stem.
Stack
How high the top of the head tube is above the bottom bracket. It decides how high the bars sit. Back or neck ache on long rides usually means more stack. A racier position means less.
I use reach and stack because they don't change with seat angle, unlike top tube length. Every design I do starts from them.
No bike to copy?
Start from your body
Measure your height and your inside leg. Stand against a wall with a book pushed up firmly between your legs and measure from the floor to the top of the book.
In the designer, the Find my size tab turns those into a starting point: roughly 2 mm more reach for every centimetre of height, and about 6.5 mm more seat tube for every centimetre of inside leg. It's only a start. Someone racing wants a longer, lower position than someone on a gravel track with a bag on the bars.
Watch: finding your starting size (18 seconds)
The other numbers
What else is worth a thought
Head angle, chainstay, BB drop and the rest
- Head angle
- Steeper steers quicker and feels lively. Slacker is calmer at speed and on steep descents. Mountain bikes run slacker than gravel and road.
- Seat angle
- Steeper puts you more over the pedals, which helps on climbs.
- Chainstay length
- Shorter feels playful. Longer is steadier and fits bigger tyres. On 32-inch wheels it also keeps the tyre clear of the seat tube.
- BB drop
- How far the bottom bracket sits below the axles. More drop is lower and more stable. Less gives more clearance over rough ground.
- Head tube length
- Sets bar height along with stack. Longer means more upright without a pile of spacers.
- Fork length and offset
- A longer fork lifts and slackens the front end. I keep the head tube and front wheel position consistent for you.
- Seat tube length
- Matters for standover and for fitting a dropper. Shorter lets you run a longer dropper.
- Tyre clearance
- Tell me the biggest tyre you might ever want. Room is easy to draw in and impossible to add later.
- Wheel size
- 29-inch, 32-inch, 700c or 26-inch fat bike. It changes the whole front end, so each frame type has its own sizes and limits.
Put it together
Design it, then I check it
Open the designer, pick a frame and a size, and change what you like. The drawing is to scale with the wheels on the ground, and it warns you if a tyre would touch the frame or your heel would hit the chainstay. Send it to me and I go through every number before I draw it in CAD for you to approve.
Questions
Frame sizing FAQ
What if I'm between sizes?
That's what bespoke is for. Instead of picking the nearest size and fixing it with a stem, you choose the reach and stack you want. Most people between sizes want a bit more reach on a standard stack, or the other way round. Easy to draw.
Can you copy the geometry of a bike I already like?
Yes. Send me the make, model and size, or its reach, stack and angles, and tell me what you'd change. In the designer the Compare my bike tab draws your numbers over the new frame so you can see the difference.
Do I need a professional bike fit?
No. If you've had one, send me the numbers and I'll build around them. If not, your current bike plus your height and inside leg is a good start, and I check every design before I quote.
How long does a bespoke frame take?
About 12 weeks from the day you approve the CAD drawing. Up to three revisions of the drawing are included.
What does it cost?
From £1,999, or £2,199 for mountain, 32-inch gravel and fat bike frames. UK delivery is free. The options list on the frames page shows what each extra costs.
Can you build the frame into a complete bike?
Yes, I do full builds. Tell me the groupset, wheels and finishing kit you want and I'll price it as a complete bike.