Originally Posted by JayBo1
I'm hoping you can provide me with a little advice. I have discovered that the drill pattern for my 2005 KTM 640 Adventure is different from my 2006 450 EXC.
I mail ordered an Excel 21"x1.6" rim for the 640 but I couldn't lace it. I finally realised the direction of the holes does not match what's required by the standard 640 hub. I took the new rim and compared it to my 450 and it is the same.
Both rims (the existing BEHR 640 rim and the new Excel rim) have a sequence of four spokes. How do you describe the drill patterns for rims?
My best amateur effort would be to talk of the first pair of holes facing "backwards" and the second pair facing "forwards". The first hole of the first pair face one side and the second hole faces the other side. The second pair repeat the first so that the "side" being faced by each spoke hole is opposite to the adjacent holes.
So the problem I have is that the sequence starts by facing the incorrect "side". Turning the hub or the rim around makes no difference. Can you confirm that it sounds like I have been supplied with an incorrectly drilled rim for my 640 application? It seems to me they have just sent a standard drill pattern KTM EXC front rim and that my 640 should be different.
By the way, I had no problems lacing the BEHR back to the hub and I have previosuly laced up Excel rims to standard hubs on previous dirtbikes (Kawasaki's). I enjoy the challenge and have had no problems with previous wheels I have laced up.
I will really appreciate your advice.
FYI....this problem is really only a PROBLEM on wheels that have hubs using nails,,ie straight spokes,,,these hubs in essence determine the indexing/sequencing of the holes drilled in your rim,,,
there are two basic patterns used today #1 is what we call the jap ,,,#2 is the european pattern,,,when you lay the wheel on a table ,,,look at the upper row of spokes closest to you,,,you will notice an inverted V which i call the tepee,,,,when you look in the tepee you'll see a spoke on the lower dimples pointing either left or right,,,,if it points left= jap pattern/indexing,,,
BWOE,, This picture is of the KTM 450 EXC front wheel.
The four 'Blue' spokes make up the sides of the two 'Tepees'. Within each of the 'Tepees' is a spoke heading to the LEFT. This gives me a "Jap" pattern index for the front wheel of my 450 EXC.
when it points toward the right you have the euro drill pattern,,,,
BWOE,, The following picture is of the KTM 640 Adventure front wheel.
The four 'Blue' spokes make up the sides of the two 'Tepees'. Within each of the 'Tepees' is a spoke heading to the RIGHT. This gives me a "Euro" pattern index for the front wheel of my 640 Adventure.
OK,,,now we can tell what rim indexing you have
Rx...if you have the wrong indexed rim,,,you have several choices,,,
1=get the correct rim for your hub
2= add or subtract one cross on one side...adding a cross requires longer spokes and vice versa for subtracting a cross.... both of these will require redrilling and contersinking the holes on that side of the rim accordingly,,in your case i would add a cross and i would do that on the disc side of the rim,,it will actually increase the strength
3=have someone like me or Buchananas redrill and figure out the lengths,,and provide the correct lenth spokes ,,,although i'm sure you have that ability sounds like,,,i've done half adozen in the past year for our ADV riders in this pickle..DO NOT con yourself into just getting the right spokes without correcting the hole angles and countersinking,,,this would lead to premature wheel failure,,,cuz the spokes tend to loosen/break where they bend at the nipple,,,
4=if we do the wheels we sometimes trade out for the right rim plus the $20 cost of the redrill/countersinking operation and whatever disparity in rim value
5=for the folks that have traditional flanged hubs,,the Rx is real easy...just flip the spokes on one side of the hub in the opposite direction,,,,Voila the spokes will go the proper dimple hole
bonus tip: while you are looking at all this i'll clue you in on the optimal location for drilling valve stem and rim-lock holes,,,when you look straight down you'll notice next to the ''teepee" is a "V''/valley,,,your valve stem and rim-lock holes should be in the 'V' /valley for easier access,,,like in the picture below,,,
BWOE,,traditionally we drill the valve stem hole opposite the point where the rim is welded together,,,under NO CIRCUMSTANCES do you want to drill the hole in the welded area,,,this spot has enough problems trying to stay stuck together,,tis the weakest spot on a rim!!!!
the extra hole for a rim-lock is usually located in the valley next to the valve stem valley,, because it makes taking the tire on n off a snap,,,
HINT ya start spooning off the tire to the left n right of the rim lock,,,putting the tire back on start opposite of the rim-lock/valve stem,,,
FYI,,,some folks drill the rim-lock hole as close to opposite of the valve stem as pictured above,,their rational is of counteracting the weight of the valve stem
Should you need a second rim rock ,,,this hole is usually located in the valley directly across from the first rim-lock hole/valley,,,this helps balance ie counter balance the weight of the first rim-lock,,,,
hope this helps ya..
PS,,,15 Jan'08,,,i just used all of JaBo1's pics and hard work and integrated it into my up-graded explanations,,,what team-work