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Tech FAQs



What is rake?
Rake is the amount of offset on a perpendicular line from the head tube centerline to the center of axle.

What is trail?
Trail is the amount of distance between where the head tube centerline and a vertical line from the center of the axle intersect the ground.

What’s the standard rear spacing on the Knobby X?
As of mid 2003 we decided to build all our Knobby X’s with a 135mm rear spacing. Reason being, we were using mountain bike hubs on all of our factory built bikes due to their superior strength by design and found that it had become more widely accepted than we had anticipated. They are still easy to set at 130mm if so desired.

There are some of the early KX’s out there that are spaced at 130mm. They can easily be reset to 135mm.

How do you prep your frames?
Before every frame leaves the Kelly factory

  1. The seat and head tube are reamed to their proper tolerance
  2. All threaded holes including the bottom bracket are chased and cleaned
  3. All bolts, hardware and bottom bracket cable guide are installed
  4. Dropout inside surfaces are cleared of powder coating to assure that the wheel slips in and out of the dropout with ease and precision.
  5. The frame is final wheel checked for alignment within a 1mm tolerance.

The idea is when you receive your Kelly frame it should be ready for assembly. It is always wise however to inspect each machined area before assembly to make sure everything is in order.

Do your bikes come with frame prep already in the tubes?
They do not. Two reasons why.

  1. We would hate to prep the frame with something other than what you would prefer. Some folks are very particular about their prep solution. Some folks don’t want prep in their frames at all.
  2. Some prep solutions contain flammable and spontaneous combustible materials. I would hate to be responsible for burning down a UPS or Fed EX facility because some prep solution oozed out of a frame, spontaneously combusted, and caught fire.

What type of BB do you use on your bikes?
All bikes are built with a 68mm wide English threaded Bottom Bracket shell.

What’s the head tube length?
We don’t have that measurement on our website so call or email and we will be glad to share the information with you.

What’s the seat tube diameter?
The seat tube diameter on all Kelly production bikes from 1995 on is 1 1/8” (28.6mm).

What’s the seat post size?
All production bikes from 2000 on are 27.2mm.

Why doesn’t my 27.2 seatpost work?
First off, not all seat posts are true to their sizing. This said, take out a pair of calipers and measure the seatpost. The calipers don’t lie. If your seatpost was slipping you will most likely find when you measure it that it was probably undersized. If it measured 27.2 and was binding or not going in all the way you probably have a pre 2000 bike that varied in seat post size (27.0 and 27.2).

What’s the stand-over?
These measurements can be found on the “production shop” section of the website. Just click on the bike you are trying to find the info on and look down the page at the technical data where the sizing chart is. It’s right there.

Is stand over a good way to determine proper fit?
Although it is sometimes a good thing to feel comfortable when you’re standing over the bike it is not always the best way to determine if a bike is the right size for you -- especially if you are looking for optimal performance.

Can I run road cranks on the Knobby X?
I suppose this is a free country and people are free to do what they want (for the most part). However, being free to do what you want and being successful don’t always go hand in hand.

The real question is: why would you want to use road cranks?

  • Is it because you wish to be over geared all the time and not have fun?
  • Is it because you want a poor chain line?
  • Is it because you want a gear and crank set that has less strength and durability?
  • Is it because you think road cranks will weigh less?
  • Is it because you think mountain cranks will make you slower?
  • Is it because you enjoy spending more time, money and grief and are the type of person who always has to figure out things the hard way?
  • Is it because you only wish to do road rides on your Knobby X and never want to ride it off road?
  • Is it because your friends who don’t know any better told you to do it?
  • All the above?

The Knobby X “Builders Choice™” specified group is the recipe for success. Whether you are piecing the bike together yourself or buying it complete from us -- save yourself (and us) a whole bunch of time, trouble and grief (that’s right – grief).

All you have to do is use our well thought out spec sheet for building a turn-key -- race winning Cross bike that will give you years and years of trouble free enjoyment.

In other words, if you want to –

  • Always have the right gear for the right situation -- whether it’s racing or recreational riding.
  • Never worry if your gearing can handle harsh off road abuse.
  • Enjoy many miles of being able to ride just about anywhere.
  • Never worry about riding the bike as hard as you can.

Then stick within the guidelines set forth in the builder’s choice spec sheet. Knobby X is one of the easiest bikes to build yet one that is most often goofed up by a wrong spec. We don’t recommend anything but the Builder’s Choice spec.

Should my cross bike be a little smaller than my road bike?
Not necessarily. It all depends on what you mean by “smaller”. The biggest mistake one can make when choosing an off road bike is to not have enough top tube length. This should always be concern #1. If you choose a bike that’s smaller proportionally than your road bike and you try to make up the rise and length with the stem you will have a bike that will most likely want to over-steer. Not good for riding fast in the dirt.

Personally I like to set my own cross bike cockpit up at least 1cm upward and 1cm inward at the handle bar clamp from where I usually sit on my road bike. At first it should feel very different and even strange. Don’t worry it’s supposed to feel that way.

A good approach to this query is to print out the “fit sheet” that I have provided on the Knobby X and Road Bike pages of my website. Find the A, B and C measurements on your road bike. Then do the math.

Provided that you and your road bike have a very good relationship, i.e. proper fit, you should have very good luck determining and setting up your cross bike.
If not, call me and I will be glad to give you a hand.

Why don’t you have lever bosses on your road bike down tube?
I think a better question to ask is: “why do you need them”? There is a barrel adjuster on every rear derailleur made these days and with a proper initial setup on the front derailleur one should never need to make a micro adjustment on it. However, if one feels the need to have such a feature, an inline barrel adjuster can easily be installed at any time.

The idea on anything (car, bike, motorcycle, etc.) that you are going to race is to exclude anything that is redundant or unnecessary.

Another benefit to having cable stops (instead of bolt on adapters) is that it’s a better means of cable housing management. The cable housing itself is in a better position so as to lessen kinking and added friction -- which leads to early wear and tear and shifting failure.

Why is my chain line off?
You tell me! If you can figure out that your chain line is “off” than you should be able to tell me why that is. The point to this riddle is that this question is asked the most by people who are building there first bike or better yet their first Knobby X. Moreover, it’s usually the shop mechanic who is only used to pulling a partially assembled bike from the box and calling what he or she performs mechanically to that bike “a build” -- or who isn’t used to building a bike from the frame up.

The point is when one sees things from a different perspective for the first time it kind of freaks them out. There is nothing actually wrong – it’s just that they have seen something for the first time and it is different.

The largest mistake people make is when they try to fit all of their old (80’s or earlier vintage) parts onto a brand new Knobby X. They find that the chain rings don’t clear the chain stay unless they use a very long BB spindle. Then the chain line is “off”. To the right about 5-10mm.

Even though I can totally appreciate that a person has a fondness for his or her old parts (for whatever reasons) the fact is that is what they are -- old parts. Knobby X, unlike a lot of cross bikes, is designed to work extremely well with a newer (better) mountain style crank. When one varies it affects a lot of things. One of them is chain line.

What are gear inches?
The amount of inches the wheel travels within 1 full rotation of the crank.

What’s a good gear for my single speed?
Depending on a person’s strength and ability level a good starting point for most types of mtb riding is anywhere between a 46” to a 52” gear. How do we figure out what is a 46” - 52” gear?
On a 26” wheel mtb you take the number of teeth on the front chainring (C) and divide them by the number of teeth on the freewheel (F). The result is the ratio (R). C/F = R. We then multiply the ratio (R) by the height (or diameter) of the wheel in inches. Rx26=gear inches.

FYI, two time One Speed World Champion, & Kelly Factory rider Stella Carey rides a 34x18, a 49” gear. So, if I have a 34-tooth chainring and 17 tooth freewheel the formula would look like this: 34 divided by 17 = 2 multiplied by 26 = 52. Or in our case 52”. You can figure out a lot of gearing solutions with this simple formula. It is especially helpful when you are setting up your 29” wheel mtb and want to match the gearing from your 26” wheel mtb.

What is a “custom”?
A custom in the Kelly dictionary is a bike frame that is designed and built as a one off or, “prototype”. A “custom” frame can be either elaborate or sometimes quite simple. Custom frames, no matter how simple or elaborate, require more production time and usually cost much more than a very similar “production” frame.

What is “customizing”?
Customizing is when we take an existing production frame and either perform custom braze-on alterations to the frame – choose a different frame color or decal selection – or choose a different parts spec other than the norm.

Do I need custom?
Good question. I realized in my first 6 years of building frames for lots of different people that I was making many of the same frames over and over. That’s why I started doing “smart sized” production frames. Early on in my career I found that I could fit at least 90% of the people that walked through the door on one of my several production sized frames. No more waiting 6 weeks or months for their bike. The customer would get the same handcrafted quality as on a “custom” without the wait or cost of a custom. It just made practical sense.

The people who end up really needing “custom” are those who either are so tall or short that they don’t fit any production size or, if they have a very short inseam and long torso (or vise versa).
The other custom candidate is the person who wants a different style or material type of bike and doesn’t mind the expense or the wait. All good if you ask me!

What’s the benefit of custom vs. production?
If you are proportioned differently than most other people i.e. very tall, small, short leg -- long torso, or short torso – long leg you are indeed a very good candidate for a custom frame.

The benefit is maximum comfort. From the way that your body fits onto the bike (cockpit) to the way your bike tracks due to proper weight distribution. After all that is the

What kind of material do you use?
We have been known to use various types of steel through the years but our flagship metal is “True Temper OX Platinum” -- a very strong, yet very light US made air hardened alloy steel. It is the same type of steel used on our US military fighter plane landing gear. If you can imagine the continuous punishment and abuse an F-18 goes through every time it hits the deck on an aircraft carrier runway just think of how much performance and reliability it will give you.

Why steel?
My criteria for material when building a bike is as follows: Very strong but not harsh, very reliable yet reasonably light (3-4 pounds), supple but not soft, responsive but smooth, snappy but not squirrelly, fun on climbs as well as descents, tracks extremely well through tight corners and is every bit as spirited in the sprint, doesn’t cost an arm and a leg to produce, is easy to have repaired if the occasion does arise, and last but not least, lasts a good long time.

Isn’t steel heavy?
Steel has always had a certain stigma in which people attribute it to being heavy. In a way it’s kind of like computers. They were much larger and slower 20 years ago. Nowadays they are much lighter and faster. The same with steel. 20 years ago a top of the line Merrckx frame weighed 5+ pounds. Nowadays one of my Bonestock frame weighs 3 to 3.5 pounds depending on the size. The other side of the coin is that the steel we use now is more than twice as strong as the steel used 20 years ago. Half the weight – twice the strength.

Do you do aluminum?
We don’t. Aluminum is a great alloy and has lots of great applications but our bag is steel for a reason. When it comes to overall performance, durability, reliability and feel, nothing rides like steel!

Do bar end shifters work on Take Off’s?

What shifters should I use to make Take Off work with 9 speed?
I like the way Dura-Ace down tube shifters work the best.

What brake levers do I use on my cross bike that will work with V-brakes?
We use only the Dia-Comp 287-V Cross Levers and have had great luck. A great compliment to the brake system is the “Paul Cross Levers”. They allow braking from the top position of the handlebars. A must for cyclocross!

What does tig welded mean?
“Tig” or rather “T.I.G.” is an abbreviation for “tungsten inert gas”. It is a type of welding in which the “T” or “tungsten” is the electrode or source of heat -- which is the business part of the torch. The “I” and “G”, or “inert gas” is Argon. Argon is an inert gas that displaces oxygen. Argon flows from the torch, surrounding the tungsten as well as the arc creating an oxygen free environment. This keeps the affected weld zone free from oxidization, which, in turn makes a strong and cleanly welded joint.

What is brazing?
If I had a dollar for every time someone called a brazed joint welded I’d be rich! Although brazing is done with an oxygen and acetelyne torch much like the ones we learned to torch weld with in high school metal shop the process is quite different.

Welding is basically melting or fusing (2400+ degrees) the joint in order to join it together. Brazing is heating (not melting) the joint and sweating (or melting) brass between, throughout or over the joint to create a bond. The brazing process is much like soldering except it uses higher heat (1600-1800 degrees) and creates a much stronger bond.

Why don’t you use lugs?
Now that it’s the year 2004 and we have mastered the technology of making high performance tubing that has more than ample strength and reinforcement on the ends -- the question is -- why add something to the bike that I don’t really need? Don’t get me wrong – I like to look at beautiful lug work as much as the next. There are many fantastic builders out there that still build with lugs. Some of them of which I happen to be good friends with. I say, “Mo power to ya”!

It’s just that when I am designing a race ready “production” bike I like to make it as simple and high performance as possible.

Lugged bikes look great. Non-lugged bikes look great. “Take your pick”, is what I say.

Do you do touch ups?
Never have. Never will.

What is powder coating?
Just like the words say – we coat the bike with powder (basically an enamel type of material ground fine like baby powder) and bake it in an oven at 400 or so degrees for about 20 to 30 minutes. As it bakes the powder melts into a glossy color much like a glaze on pottery. It’s non-toxic, very earth friendly, very tough and looks great!

Can you color match with powder coating?
There is no such thing as a perfect match. Ask any painter and they will tell you. However, powder coating has come along way in the last ten years. That said there are oodles of colors to choose from. I’m sure we can find something that is right for you.

Can you do custom colors?
There are hundreds of colors that are available to us. For an up-charge starting price of $35 we offer colors other than our production colors.

Who buys your bikes?
Kind of a funny question but one we are asked from time to time -- so, I suppose it deserves an answer. The answer is: All kinds of folks. We’re not some kind of “members only” club were you need some sort of credentials in order to belong. Our bikes price range is reflective of it being “high end”, however, we sell to many first time buyers who are very happy to avoid the proverbial step ladder that many people think they need to climb before finally owning the bike they really want.

Where can I buy a Kelly?
Kelly Bike Co has always serviced multiple distribution channels. If there is not a Kelly dealer near you – and your favorite dealer can’t or won’t help you – we are glad to serve you. If your local dealer wants to become a Kelly dealer we are glad to serve them.


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Photos: Roman Roth